[ { "id": "https://authors.library.caltech.edu/records/vfqne-dga34", "eprint_status": "archive", "datestamp": "2024-03-06 00:24:01", "lastmod": "2024-03-06 00:24:01", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Tsamopoulos-Alexandros-J", "name": { "family": "Tsamopoulos", "given": "Alexandros J." }, "orcid": "0009-0003-5924-5512" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Ion Conductivity in Salt-Doped Polymers: Combined Effects of Temperature and Salt Concentration", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "
© 2024 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.
\n\nThis research was supported by funding from Hong Kong Quantum AI Lab, AIR@InnoHK of the Hong Kong Government. The authors thank Prof. Lisa Hall and Dr. Kuan-Hsuan Shen for providing the LAMMPS solvation potential source code.
\nThe authors declare no competing financial interest.
\n\nSimulation details, determination of the glass transition, ion–polymer coordination, Rouse-mode analysis and friction coefficient, specific conductivity at infinite dilution, and VFT analysis (PDF)
\nWe construct a coarse-grained molecular dynamics model based on poly(ethylene oxide) and lithium bis(trifluoromethane)sulfonimide salt to examine the combined effects of temperature and salt concentration on the transport properties. Salt doping notably slows the dynamics of polymer chains and reduces ion diffusivity, resulting in a glass transition temperature increase proportional to the salt concentration. The polymer diffusion is shown to be well represented by a modified Vogel–Fulcher–Tamman (M-VFT) equation that accounts for both the temperature and salt concentration dependence. Furthermore, we find that, at any temperature, the concentration dependence of the conductivity is well described by the product of its infinite dilution value and a correction factor accounting for the reduced segmental mobility with increasing salt concentration. These results highlight the important role of polymer segmental mobility in the salt concentration dependence of ion conductivity for temperatures near and above the glass transition.
\n\u00a9 2023 American Physical Society.
\n\nThis research is supported by funding from Hong Kong Quantum AI Lab, AIR@InnoHK of Hong Kong Government. This research used resources of the Center for Functional Nanomaterials (CFN), which is a U.S. Department of Energy Office of Science User Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704. We thank Dr. Andrew Ylitalo for useful discussions.
", "abstract": "Mixing solutions of oppositely charged macromolecules can result in liquid-liquid phase separation into a polymer-rich coacervate phase and a polymer-poor supernatant phase. Here, we show that charge asymmetry in the constituent polymers can slow down the coarsening dynamics, with an apparent growth exponent that deviates from the well-known 1/3 for neutral systems and decreases with increasing degrees of charge asymmetry. Decreasing solvent quality accelerates the coarsening dynamics for asymmetric mixtures but slows down the coarsening dynamics for symmetric mixtures. We rationalize these results by examining the interaction potential between merging droplets.
", "date": "2023-11-24", "date_type": "published", "publication": "Physical Review Letters", "volume": "131", "number": "21", "publisher": "American Physical Society", "pagerange": "218201", "issn": "0031-9007", "official_url": "https://authors.library.caltech.edu/records/g88t0-aza26", "funders": { "items": [ { "grant_number": "DE-SC0012704" } ] }, "doi": "10.1103/physrevlett.131.218201", "primary_object": { "basename": "Coarsening_SM.pdf", "url": "https://authors.library.caltech.edu/records/g88t0-aza26/files/Coarsening_SM.pdf" }, "related_objects": [ { "basename": "PhysRevLett.131.218201.pdf", "url": "https://authors.library.caltech.edu/records/g88t0-aza26/files/PhysRevLett.131.218201.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Chen, Shensheng and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/h54hj-n9k23", "eprint_status": "archive", "datestamp": "2023-09-18 20:34:27", "lastmod": "2023-09-18 20:34:27", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "name": { "family": "Balzer", "given": "Christopher" }, "orcid": "0000-0002-9767-8437" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Electroresponse of weak polyelectrolyte brushes", "ispublished": "pub", "full_text_status": "public", "keywords": "Surfaces and Interfaces; General Materials Science; General Chemistry; Biophysics; Biotechnology", "note": "\u00a9 The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
\n\nThe authors acknowledge Dr. Alejandro Gallegos for useful discussions. C.B. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0020347. Z.-G.W acknowledges Hong Kong Quantum AI Lab, AIR@InnoHK of Hong Kong Government.
This article is dedicated to Fyl Pincus, whose prolific and insightful contributions to the fields of condensed matter, polymer, and soft matter physics have left a lasting impact. The work presented here draws particular inspiration from Fyl's groundbreaking research on polyelectrolyte brushes.
\n\nC.B. and Z.-G.W. participated in the project conception, developmentment of theory, data collection, and in preparation of the manuscript.
\n\nThe datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
", "abstract": "End-tethered polyelectrolytes are widely used to modify substrate properties, particularly for lubrication or wetting. External stimuli, such as pH, salt concentration, or an electric field, can induce profound structural responses in weak polyelectrolyte brushes, which can be utilized to further tune substrate properties. We study the structure and electroresponsiveness of weak polyacid brushes using an inhomogeneous theory that incorporates both electrostatic and chain connectivity correlations at the Debye\u2013H\u00fcckel level. Our calculation shows that a weak polyacid brush swells under the application of a negative applied potential, in agreement with recent experimental observation. We rationalize this behavior using a scaling argument that accounts for the effect of the surface charge. We also show that the swelling behavior has a direct influence on the differential capacitance, which can be modulated by the solvent quality, pH, and salt concentration.
", "date": "2023-09", "date_type": "published", "publication": "European Physical Journal E", "volume": "46", "number": "9", "publisher": "Springer Science and Business Media LLC", "pagerange": "82", "issn": "1292-8941", "official_url": "https://authors.library.caltech.edu/records/h54hj-n9k23", "funders": { "items": [ { "grant_number": "DE-SC0020347" }, { "agency": "Hong Kong Quantum AI Lab" } ] }, "doi": "10.1140/epje/s10189-023-00341-3", "pmcid": "PMC10501941", "primary_object": { "basename": "s10189-023-00341-3.pdf", "url": "https://authors.library.caltech.edu/records/h54hj-n9k23/files/s10189-023-00341-3.pdf" }, "related_objects": [ { "basename": "10189_2023_341_MOESM1_ESM.pdf", "url": "https://authors.library.caltech.edu/records/h54hj-n9k23/files/10189_2023_341_MOESM1_ESM.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Balzer, Christopher and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/v7r1j-aas97", "eprint_status": "archive", "datestamp": "2023-10-25 18:57:40", "lastmod": "2023-10-25 18:57:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chen-ShenSheng", "name": { "family": "Chen", "given": "Shensheng" }, "orcid": "0000-0002-6427-935X" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Using Implicit-Solvent Potentials to Extract Water Contributions to Enthalpy\u2013Entropy Compensation in Biomolecular Associations", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Surfaces, Coatings and Films; Physical and Theoretical Chemistry; Enthalpy; Entropy; Molecular mechanics; Polymers; Temperature dependence", "note": "\u00a9 2023 The Authors. Published by American Chemical Society. Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
\n\nThis research was supported by funding from Hong Kong Quantum AI Lab, AIR@InnoHK of the Hong Kong Government. This research used the Theory and Computation facility of the Center for Functional Nanomaterials (CFN), which is a U.S. Department of Energy Office of Science User Facility, at the Brookhaven National Laboratory under Contract no. DE-SC0012704.
\n\njp3c03799.pdf - published article
jp3c03799_si_001.pdf - supplemental information
", "abstract": "
Biomolecular assembly typically exhibits enthalpy\u2013entropy compensation (EEC) behavior whose molecular origin remains a long-standing puzzle. While water restructuring is believed to play an important role in EEC, its contribution to the entropy and enthalpy changes, and how these changes relate to EEC, remains poorly understood. Here, we show that water reorganization entropy/enthalpy can be obtained by exploiting the temperature dependence in effective, implicit-solvent potentials. We find that the different temperature dependencies in the hydrophobic interaction, rooted in water reorganization, result in substantial variations in the entropy/enthalpy change, which are responsible for EEC. For lower-critical-solution-temperature association, water reorganization entropy dominates the free-energy change at the expense of enthalpy; for upper-critical-solution-temperature association, water reorganization enthalpy drives the process at the cost of entropy. Other effects, such as electrostatic interaction and conformation change of the macromolecules, contribute much less to the variations in entropy/enthalpy.
", "date": "2023-08-03", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "127", "number": "30", "publisher": "American Chemical Society", "pagerange": "6825-6832", "issn": "1520-6106", "official_url": "https://authors.library.caltech.edu/records/v7r1j-aas97", "rights": "The Creative Commons Attribution license allows re-distribution and re-use of a licensed work on the condition that the creator is appropriately credited.", "funders": { "items": [ { "agency": "United States Department of Energy", "grant_number": "DE-SC0012704" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/acs.jpcb.3c03799", "pmcid": "PMC10405215", "primary_object": { "basename": "jp3c03799.pdf", "url": "https://authors.library.caltech.edu/records/v7r1j-aas97/files/jp3c03799.pdf" }, "related_objects": [ { "basename": "jp3c03799_si_001.pdf", "url": "https://authors.library.caltech.edu/records/v7r1j-aas97/files/jp3c03799_si_001.pdf" } ], "resource_type": "article", "pub_year": "2023", "author_list": "Chen, Shensheng and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/dfcd3-qm089", "eprint_id": 122335, "eprint_status": "archive", "datestamp": "2023-08-22 21:24:10", "lastmod": "2023-10-20 20:26:08", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Dorfman-Kevin-D", "name": { "family": "Dorfman", "given": "Kevin D." }, "orcid": "0000-0003-0065-5157" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Liquid-Like States in Micelle-Forming Diblock Copolymer Melts", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2023 American Chemical Society. \n\nWe thank Frank S. Bates, David C. Morse, Timothy P. Lodge, and Benjamin R. Magruder for useful discussions. K.D.D. acknowledges the gracious hospitality of the California Institute of Technology during portions of this work. Z.-G.W. acknowledges support by Hong Kong Quantum AI Lab, AIR@InnoHK of Hong Kong Government. Computational resources were provided by the Minnesota Supercomputing Institute. \n\nAuthor Contributions: CRediT: Kevin D. Dorfman conceptualization (supporting), data curation (lead), investigation (lead), methodology (equal), software (lead), writing-original draft (lead), writing-review & editing (equal); Zhen-Gang Wang conceptualization (lead), investigation (supporting), methodology (equal), writing-review & editing (equal). \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - mz3c00259_si_001.pdf
", "abstract": "Large cell self-consistent field theory (SCFT) solutions for a neat, micelle-forming diblock copolymer melt, initialized using the structure of a Lennard-Jones fluid, reveal the existence of a vast number of liquid-like states, with free energies of order 10\u207b\u00b3 k_(B)T per chain higher than the body-centered cubic (bcc) state near the order\u2013disorder transition (ODT). Computation of the structure factor for these liquids at temperatures below the ODT indicates that their intermicellar distance is slightly swollen compared to bcc. In addition to providing a mean-field picture of the disordered micellar state, the number of liquid-like states and their near-degeneracy with the equilibrium bcc morphology suggest that self-assembly of micelle-forming diblock copolymers navigates a rugged free energy landscape with many local minima. This picture provides a basis for the anomalously slow ordering kinetics of particle-forming diblock copolymer melts observed in experiments.", "date": "2023-07-18", "date_type": "published", "publication": "ACS Macro Letters", "volume": "12", "number": "7", "publisher": "American Chemical Society", "pagerange": "980-985", "id_number": "CaltechAUTHORS:20230717-55915200.30", "issn": "2161-1653", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230717-55915200.30", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1021/acsmacrolett.3c00259", "primary_object": { "basename": "mz3c00259_si_001.pdf", "url": "https://authors.library.caltech.edu/records/dfcd3-qm089/files/mz3c00259_si_001.pdf" }, "resource_type": "article", "pub_year": "2023", "author_list": "Dorfman, Kevin D. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/e2z96-dw281", "eprint_id": 121629, "eprint_status": "archive", "datestamp": "2023-08-22 20:58:41", "lastmod": "2023-10-20 15:40:49", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Varner-Samuel", "name": { "family": "Varner", "given": "Samuel" }, "orcid": "0000-0002-1365-1027" }, { "id": "Balzer-Christopher", "name": { "family": "Balzer", "given": "Christopher" }, "orcid": "0000-0002-9767-8437" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Entropic Origin of Ionic Interactions in Polar Solvents", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Surfaces, Coatings and Films; Physical and Theoretical Chemistry", "note": "\u00a9 2023 The Authors. Published by American Chemical Society. Attribution 4.0 International (CC BY 4.0) \n\nPublished as part of The Journal of Physical Chemistry virtual special issue \"Pablo G. Debenedetti Festschrift\". \n\nThe authors thank Professor Bilin Zhuang for helpful discussions. S.V. and C.B. are supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0022158 and DE-SC0020347, respectively. Partial support for this research is provided by Hong Kong Quantum AI Lab, AIR@InnoHK of Hong Kong Government. \n\nThe authors declare no competing financial interest.\n\nPublished - jp3c00588.pdf
", "abstract": "Implicit solvent models that reduce solvent degrees of freedom into effective interaction potentials are widely used in the study of soft materials and biophysical systems. For electrolyte and polyelectrolyte solutions, coarse-graining the solvent degrees of freedom into an effective dielectric constant embeds entropic contributions into the temperature dependence of the dielectric constant. Properly accounting for this electrostatic entropy is essential to discern whether a free energy change is enthalpically or entropically driven. We address the entropic origin of electrostatic interactions in a dipolar solvent and provide a clarified physical picture of the solvent dielectric response. We calculate the potential of mean force (PMF) between two oppositely charged ions in a dipolar solvent using molecular dynamics and dipolar self-consistent field theory. We find with both techniques that the PMF is dominated by the entropy gain from the dipole release, owing to the diminished orientational polarization of the solvent. We also find that the relative contribution of the entropy to the free energy change is nonmonotonic with temperature. We expect that our conclusions are applicable to a broad range of problems involving ionic interactions in polar solvents.", "date": "2023-05-18", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "127", "number": "19", "publisher": "American Chemical Society", "pagerange": "4328-4337", "id_number": "CaltechAUTHORS:20230530-441768000.67", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230530-441768000.67", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0020347" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0022158" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1021/acs.jpcb.3c00588", "pmcid": "PMC10201535", "primary_object": { "basename": "jp3c00588.pdf", "url": "https://authors.library.caltech.edu/records/e2z96-dw281/files/jp3c00588.pdf" }, "resource_type": "article", "pub_year": "2023", "author_list": "Varner, Samuel; Balzer, Christopher; et el." }, { "id": "https://authors.library.caltech.edu/records/92k5d-2kj79", "eprint_id": 121063, "eprint_status": "archive", "datestamp": "2023-08-22 20:28:45", "lastmod": "2023-10-18 18:08:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhenhua", "name": { "family": "Wang", "given": "Zhenhua" }, "orcid": "0000-0002-6878-6279" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Shi-An-Chang", "name": { "family": "Shi", "given": "An-Chang" }, "orcid": "0000-0003-1379-7162" }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } } ] }, "title": "Behaviors of a Polymer Chain in Channels: From Zimm to Rouse Dynamics", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2023 American Chemical Society. \n\nThis work was supported by the National Key R&D Program of China (grant no. 2020YFA0713601), the National Natural Science Foundation of China (grant nos. 21790340 and 22073092), and the Key Research Program of Frontier Sciences, CAS (grant no. QYZDY-SSW-SLH027). Additional support for Y.L. was provided by the Youth Innovation Promotion Association of CAS (grant no. Y202054). We thank the anonymous reviewers, whose constructive comments have helped improve the presentation of our work. \n\nThe authors declare no competing financial interest.", "abstract": "The effects of confinement and hydrodynamic interactions on single-chain diffusion behaviors are studied by using a combination of molecular dynamics and multiparticle collision dynamics simulations. For polymers in free space, the simulation results showed that the diffusion coefficient D\u221e for long chains scales with the chain length N as D_\u221e \u223c N^(\u2013\u03bd) (\u03bd = 0.588), consistent with the Zimm dynamics, but it deviates from the Zimm dynamics for short chains. For polymers confined in channels with width H, the diffusion coefficient is found to follow two different scaling relations. The observed behaviors could be understood by introducing a microscopic hydrodynamic length \u03be\u2095, below which the overall effect of hydrodynamic interactions becomes less important. For a confined chain, the diffusion behavior exhibits a crossover from Zimm (nondraining) to Rouse (free draining) dynamics as the channel size H decreases. When H is larger than \u03be\u2095, the confinement experienced by the polymer chain is weak and the diffusion coefficient scales as D \u223c H^(0.7), in accordance with the prediction of blob theory; when H is smaller than \u03be\u2095, D becomes independent of H, implying a free draining condition. A general analytical expression of D is derived by extending the partially permeable sphere model to the blob scale, which gives a quantitative description of the transition from Zimm to Rouse dynamics as H decreases.", "date": "2023-03-28", "date_type": "published", "publication": "Macromolecules", "volume": "56", "number": "6", "publisher": "American Chemical Society", "pagerange": "2447-2453", "id_number": "CaltechAUTHORS:20230420-711199500.14", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230420-711199500.14", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Ministry of Science and Technology (China)", "grant_number": "2020YFA0713601" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21790340" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073092" }, { "agency": "Chinese Academy of Sciences", "grant_number": "QYZDY-SSW-SLH027" }, { "agency": "Chinese Academy of Sciences", "grant_number": "Y202054" } ] }, "doi": "10.1021/acs.macromol.3c00013", "resource_type": "article", "pub_year": "2023", "author_list": "Wang, Zhenhua; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/e57vb-23m28", "eprint_id": 118949, "eprint_status": "archive", "datestamp": "2023-08-22 18:42:27", "lastmod": "2023-10-24 23:46:52", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Wang-Zheng", "name": { "family": "Wang", "given": "Zheng" }, "orcid": "0000-0003-3651-5287" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Conformation Transition of a Homopolymer Chain in Binary Mixed Solvents", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "P.Z. is indebted to valuable discussions with Prof. Baohui Li and acknowledges the financial support provided by the National Natural Science Foundation of China (22073016 and 21803011) and the award of Shanghai Dongfang Scholar. Z.-G.W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd.", "abstract": "On the basis of a minimal lattice model, we apply the Wang\u2013Landau Monte Carlo (MC) algorithm and a Flory-type mean-field theory to investigate the conformation of a homopolymer chain in a mixture of binary solvents A and B. This MC method enables us to accurately locate the conformation transitions and to determine their nature over a large parameter space. We find that in a good solvent A, adding a small amount of better solvent B causes a continuous collapse transition when the difference in the solvent quality is large. Increasing the fraction of solvent B results in a smooth reswelling of the chain. We explain these findings by the delicate interplay among the mixing entropy of binary solvents, the chain conformational entropy, and the competition in the interactions between the monomer and the two solvents.", "date": "2023-01-10", "date_type": "published", "publication": "Macromolecules", "volume": "56", "number": "1", "publisher": "American Chemical Society", "pagerange": "153-165", "id_number": "CaltechAUTHORS:20230125-515005200.31", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230125-515005200.31", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "22073016" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21803011" }, { "agency": "Shanghai Dongfang Scholar" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1021/acs.macromol.2c01896", "resource_type": "article", "pub_year": "2023", "author_list": "Zhang, Pengfei; Wang, Zheng; et el." }, { "id": "https://authors.library.caltech.edu/records/yfm0j-fbr47", "eprint_id": 118810, "eprint_status": "archive", "datestamp": "2023-08-22 18:32:48", "lastmod": "2023-10-24 23:30:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mantha-Sriteja", "name": { "family": "Mantha", "given": "Sriteja" }, "orcid": "0000-0001-7813-0903" }, { "id": "Chao-Huikuan", "name": { "family": "Chao", "given": "Huikuan" }, "orcid": "0000-0001-9930-3586" }, { "id": "Ylitalo-Andrew-S", "name": { "family": "Ylitalo", "given": "Andrew S." }, "orcid": "0000-0003-4086-3508" }, { "id": "Fitzgibbons-Thomas-C", "name": { "family": "Fitzgibbons", "given": "Thomas C." }, "orcid": "0000-0002-8330-1102" }, { "id": "Zhou-Weijun", "name": { "family": "Zhou", "given": "Weijun" } }, { "id": "Ginzburg-Valeriy-V", "name": { "family": "Ginzburg", "given": "Valeriy V." }, "orcid": "0000-0002-2775-5492" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Surfactant in a Polyol-CO\u2082 Mixture: Insights from a Classical Density Functional Theory Study", "ispublished": "pub", "full_text_status": "public", "keywords": "Electrochemistry; Spectroscopy; Surfaces and Interfaces; Condensed Matter Physics; General Materials Science", "note": "\u00a9 2022 The Authors. Published by American Chemical Society. Attribution 4.0 International (CC BY 4.0) \n\nThe authors acknowledge Dow, Inc., for the financial support through the Dow\u2013Caltech university partnership initiative (UPI). The authors benefited greatly from the discussions with our UPI experimental collaborators, Prof. Julie Kornfield and Prof. Richard Flagan. S.M. thanks Chris Balzer for discussions and useful comments. A.S.Y. acknowledges the support of the National Science Foundation Graduate Research Fellowship Program under Grant DGE-1745301. \n\nThe authors declare no competing financial interest.\n\nPublished - la2c02913.pdf
", "abstract": "Silicone\u2013polyether (SPE) surfactants, made of a polydimethyl-siloxane (PDMS) backbone and polyether branches, are commonly used as additives in the production of polymeric foams with improved properties. A key step in the production of polymeric foams is the nucleation of gas bubbles in the polymer matrix upon supersaturation of dissolved gas. However, the role of SPE surfactants in the nucleation of gas bubbles is not well understood. In this study, we use classical density functional theory to investigate the effect of an SPE surfactant on the nucleation of CO\u2082 bubbles in a polyol foam formulation. We find that the addition of an SPE surfactant leads to a \u223c3-fold decrease in the polyol\u2013CO\u2082 interfacial tension at the surfactant's critical micelle concentration. Additionally, the surfactant is found to reduce the free energy barrier and affect the minimum free energy pathway (MFEP) associated with CO\u2082 bubble nucleation. In the absence of a surfactant, a CO\u2082-rich bubble nucleates from a homogeneous CO\u2082-supersaturated polyol solution by following an MFEP characterized by a single nucleation barrier. Adding a surfactant results in a two-step nucleation process with reduced free energy barriers. The first barrier corresponds to the formation of a spherical aggregate with a liquid-like CO\u2082 core. This spherical aggregate then grows into a CO\u2082-rich bubble (spherical aggregate with a vapor-like CO\u2082 core) of a critical size representing the second barrier. We hypothesize that the stronger affinity of CO\u2082 for PDMS (than polyether) stabilizes the spherical aggregate with the liquid-like CO\u2082 core, leading to a lower free energy barrier for CO\u2082 bubble nucleation. Stabilization of such an aggregate during the early stages of the nucleation may lead to foams with more, smaller bubbles, which can improve their microstrustural features and insulating abilities.", "date": "2022-12-27", "date_type": "published", "publication": "Langmuir", "volume": "38", "number": "51", "publisher": "American Chemical Society", "pagerange": "16172-16182", "id_number": "CaltechAUTHORS:20230117-369491100.6", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230117-369491100.6", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1745301" } ] }, "doi": "10.1021/acs.langmuir.2c02913", "pmcid": "PMC9798868", "primary_object": { "basename": "la2c02913.pdf", "url": "https://authors.library.caltech.edu/records/yfm0j-fbr47/files/la2c02913.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Mantha, Sriteja; Chao, Huikuan; et el." }, { "id": "https://authors.library.caltech.edu/records/d9raj-62d48", "eprint_id": 117965, "eprint_status": "archive", "datestamp": "2023-08-22 18:00:11", "lastmod": "2023-10-23 20:11:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Varner-Samuel", "name": { "family": "Varner", "given": "Samuel" }, "orcid": "0000-0002-1365-1027" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of dilution in ionic liquid supercapacitors", "ispublished": "pub", "full_text_status": "public", "keywords": "Physical and Theoretical Chemistry; General Physics and Astronomy", "note": "S. V. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0022158. Z.-G. W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd.", "abstract": "Room-temperature ionic liquids (RTILs) are synthetic electrolytes that have a large electrochemical stability window, making them attractive candidates for electric double-layer capacitor (EDLC) applications. Due to their high viscosities and low ionic conductivities, RTILs are often diluted with organic solvent for practical use. We study the effects of dilution on the performance of RTIL EDLCs using a simple mean-field model. We find that dilution diminishes the unfavorable hysteresis that results from a spontaneous surface charge separation (SSCS). As a result, the RTIL concentration can be used to modulate the proximity to the SSCS transition, and maximize capacitance. The interplay between the concentration and the correlation strength gives rise to complex zero-potential phase behavior, including a tricritical point and a \u03bb-line, very similar to the Blume\u2013Capel dilute Ising model. Additionally, electrodes that are solvophilic aid in the prevention of SSCS by drawing solvent molecules to the electrode and displacing ions. Solvophilic electrodes give rise to a phase transition at finite potential where the surface charge rapidly increases with a small increase in potential, leading to a substantial increase in capacitance and energy storage.", "date": "2022-10-28", "date_type": "published", "publication": "Physical Chemistry Chemical Physics", "volume": "24", "number": "44", "publisher": "Royal Society of Chemistry", "pagerange": "27362-27374", "id_number": "CaltechAUTHORS:20221121-712922500.32", "issn": "1463-9076", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20221121-712922500.32", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0022158" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1039/d2cp03398d", "resource_type": "article", "pub_year": "2022", "author_list": "Varner, Samuel and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/6gyv9-k9s16", "eprint_id": 117821, "eprint_status": "archive", "datestamp": "2023-08-22 17:58:34", "lastmod": "2023-10-24 22:40:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ghosh-Ashesh", "name": { "family": "Ghosh", "given": "Ashesh" }, "orcid": "0000-0002-3312-6107" }, { "id": "MacPherson-Quinn", "name": { "family": "MacPherson", "given": "Quinn" }, "orcid": "0000-0003-2719-6018" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Spakowitz-Andrew-J", "name": { "family": "Spakowitz", "given": "Andrew J." }, "orcid": "0000-0002-0585-1942" } ] }, "title": "Semiflexible polymer solutions. II. Fluctuations and Frank elastic constants", "ispublished": "pub", "full_text_status": "public", "keywords": "Physical and Theoretical Chemistry; General Physics and Astronomy", "note": "This work was supported by the NSF program Condensed Matter and Materials Theory (Grant No. DMR-1855334).", "abstract": "We study the collective elastic behavior of semiflexible polymer solutions in a nematic liquid-crystalline state using polymer field theory. Our polymer field-theoretic model of semiflexible polymer solutions is extended to include second-order fluctuation corrections to the free energy, permitting the evaluation of the Frank elastic constants based on orientational order fluctuations in the nematic state. Our exact treatment of wormlike chain statistics permits the evaluation of behavior from the nematic state, thus accurately capturing the impact of single-chain behavior on collective elastic response. Results for the Frank elastic constants are presented as a function of aligning field strength and chain length, and we explore the impact of conformation fluctuations and hairpin defects on the twist, splay, and bend moduli. Our results indicate that the twist elastic constant K_twist is smaller than both bend and splay constants (K_bend and K_splay, respectively) for the entire range of polymer rigidity. Splay and bend elastic constants exhibit regimes of dominance over the range of chain stiffness, where K_splay > K_bend for flexible polymers (large-N limit) while the opposite is true for rigid polymers. Theoretical analysis also suggests the splay modulus tracks exactly to that of the end-to-end distance in the transverse direction for semiflexible polymers at intermediate to large-N. These results provide insight into the role of conformation fluctuations and hairpin defects on the collective response of polymer solutions.", "date": "2022-10-21", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "157", "number": "15", "publisher": "American Institute of Physics", "pagerange": "Art. No. 154906", "id_number": "CaltechAUTHORS:20221110-429809700.5", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20221110-429809700.5", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-1855334" } ] }, "doi": "10.1063/5.0120526", "resource_type": "article", "pub_year": "2022", "author_list": "Ghosh, Ashesh; MacPherson, Quinn; et el." }, { "id": "https://authors.library.caltech.edu/records/vxjm8-vmf10", "eprint_id": 122518, "eprint_status": "archive", "datestamp": "2023-08-22 17:38:34", "lastmod": "2023-11-16 00:00:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chen-Shensheng", "name": { "family": "Chen", "given": "Shensheng" }, "orcid": "0000-0002-6427-935X" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Driving force and pathway in polyelectrolyte complex coacervation", "ispublished": "pub", "full_text_status": "public", "keywords": "Multidisciplinary", "note": "\u00a9 2022 the Author(s). Published by PNAS. This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND). \n\nThis research is supported by funding from Hong Kong Quantum AI Lab Ltd. We thank the general computation time allocated by the resources of the Center for Functional Nanomaterials, which is a US Department of Energy Office of Science User Facility, at Brookhaven National Laboratory under Contract DE-SC0012704. We thank Prof. M. Muthukumar for bringing our attention to his forthcoming book. \n\nAuthor contributions: S.C. and Z.-G.W. designed research, performed research, analyzed data, and wrote the paper. \n\nThe authors declare no competing interest.\n\nPublished - pnas.2209975119.pdf
Supplemental Material - pnas.2209975119.sapp.pdf
", "abstract": "There is notable discrepancy between experiments and coarse-grained model studies regarding the thermodynamic driving force in polyelectrolyte complex coacervation: experiments find the free energy change to be dominated by entropy, while simulations using coarse-grained models with implicit solvent usually report a large, even dominant energetic contribution in systems with weak to intermediate electrostatic strength. Here, using coarse-grained, implicit-solvent molecular dynamics simulation combined with thermodynamic analysis, we study the potential of mean force (PMF) in the two key stages on the coacervation pathway for symmetric polyelectrolyte mixtures: polycation\u2013polyanion complexation and polyion pair\u2013pair condensation. We show that the temperature dependence in the dielectric constant of water gives rise to a substantial entropic contribution in the electrostatic interaction. By accounting for this electrostatic entropy, which is due to solvent reorganization, we find that under common conditions (monovalent ions, room temperature) for aqueous systems, both stages are strongly entropy-driven with negligible or even unfavorable energetic contributions, consistent with experimental results. Furthermore, for weak to intermediate electrostatic strengths, this electrostatic entropy, rather than the counterion-release entropy, is the primary entropy contribution. From the calculated PMF, we find that the supernatant phase consists predominantly of polyion pairs with vanishingly small concentration of bare polyelectrolytes, and we provide an estimate of the spinodal of the supernatant phase. Finally, we show that prior to contact, two neutral polyion pairs weakly attract each other by mutually induced polarization, providing the initial driving force for the fusion of the pairs.", "date": "2022-09-06", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "119", "number": "36", "publisher": "National Academy of Sciences", "pagerange": "e2209975119", "id_number": "CaltechAUTHORS:20230725-705994000.20", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230725-705994000.20", "funders": { "items": [ { "agency": "Hong Kong Quantum AI Lab Ltd." }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0012704" } ] }, "doi": "10.1073/pnas.2209975119", "pmcid": "PMC9457374", "primary_object": { "basename": "pnas.2209975119.pdf", "url": "https://authors.library.caltech.edu/records/vxjm8-vmf10/files/pnas.2209975119.pdf" }, "related_objects": [ { "basename": "pnas.2209975119.sapp.pdf", "url": "https://authors.library.caltech.edu/records/vxjm8-vmf10/files/pnas.2209975119.sapp.pdf" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Chen, Shensheng and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/smzr5-fh725", "eprint_id": 116722, "eprint_status": "archive", "datestamp": "2023-08-22 17:27:49", "lastmod": "2023-10-24 21:09:43", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ylitalo-Andrew-S", "name": { "family": "Ylitalo", "given": "Andrew S." }, "orcid": "0000-0003-4086-3508" }, { "id": "Chao-Huikuan", "name": { "family": "Chao", "given": "Huikuan" }, "orcid": "0000-0001-9930-3586" }, { "id": "Walker-Pierre-J", "name": { "family": "Walker", "given": "Pierre J." }, "orcid": "0000-0001-8628-6561" }, { "id": "Crosthwaite-Jacob", "name": { "family": "Crosthwaite", "given": "Jacob" }, "orcid": "0000-0003-4950-3576" }, { "id": "Fitzgibbons-Thomas-C", "name": { "family": "Fitzgibbons", "given": "Thomas C." }, "orcid": "0000-0002-8330-1102" }, { "id": "Ginzburg-Valeriy-G", "name": { "family": "Ginzburg", "given": "Valeriy G." } }, { "id": "Zhou-Weijun", "name": { "family": "Zhou", "given": "Weijun" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Di-Maio-Ernesto", "name": { "family": "Di Maio", "given": "Ernesto" }, "orcid": "0000-0002-3276-174X" }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" } ] }, "title": "Competition between CO\u2082-philicity and Mixing Entropy Leads to CO\u2082 Solubility Maximum in Polyether Polyols", "ispublished": "pub", "full_text_status": "public", "keywords": "Industrial and Manufacturing Engineering; General Chemical Engineering; General Chemistry", "note": "\u00a9 2022 The Authors. Published by American Chemical Society\nPermits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). \n\nThe authors express their gratitude to Prof. Richard C. Flagan of Caltech for helpful discussions while planning, performing, and writing up this work and to Dr. Sriteja Mantha of Caltech for help with the group contribution method. The authors would also like to thank Dr. Maria Rosaria Di Caprio for help training A.S.Y. to use G-ADSA at the University of Naples. A.S.Y. acknowledges support by the Dow University Partnership Initiative and the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. \n\nThe authors declare no competing financial interest.\n\nPublished - ie2c02396.pdf
Supplemental Material - ie2c02396_si_001.pdf
", "abstract": "In carbon dioxide-blown polymer foams, the solubility of carbon dioxide (CO\u2082) in the polymer profoundly shapes the structure and, consequently, the physical properties of the foam. One such foam is polyurethane-commonly used for thermal insulation, acoustic insulation, and cushioning which increasingly relies on CO\u2082 to replace environmentally harmful blowing agents. Polyurethane is produced through the reaction of isocyanate and polyol, of which the polyol has the higher capacity for dissolving CO\u2082. While previous studies have suggested the importance of the effect of hydroxyl end groups on CO\u2082 solubility in short polyols (<1000 g/mol), their effect in polyols with higher molecular weight (\u22651000 g/mol) and higher functionality (>2 hydroxyls per chain)-as are commonly used in polyurethane foams-has not been reported. Here, we show that the solubility of CO\u2082 in polyether polyols decreases with molecular weight above 1000 g/mol and decreases with functionality using measurements performed by gravimetry-axisymmetric drop-shape analysis. The nonmonotonic effect of molecular weight on CO\u2082 solubility results from the competition between effects that reduce CO\u2082 solubility (lower mixing entropy) and effects that increase CO\u2082 solubility (lower ratio of hydroxyl end groups to ether backbone groups). To generalize our measurements, we modeled the CO\u2082 solubility using a perturbed chain-statistical associating fluid theory (PC-SAFT) model, which we validated by showing that a density functional theory model based on the PC-SAFT free energy accurately predicted the interfacial tension.", "date": "2022-08-31", "date_type": "published", "publication": "Industrial & Engineering Chemistry Research", "volume": "61", "number": "34", "publisher": "American Chemical Society", "pagerange": "12835-12844", "id_number": "CaltechAUTHORS:20220906-252603000", "issn": "0888-5885", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220906-252603000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1745301" } ] }, "doi": "10.1021/acs.iecr.2c02396", "primary_object": { "basename": "ie2c02396.pdf", "url": "https://authors.library.caltech.edu/records/smzr5-fh725/files/ie2c02396.pdf" }, "related_objects": [ { "basename": "ie2c02396_si_001.pdf", "url": "https://authors.library.caltech.edu/records/smzr5-fh725/files/ie2c02396_si_001.pdf" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Ylitalo, Andrew S.; Chao, Huikuan; et el." }, { "id": "https://authors.library.caltech.edu/records/hr0g9-xps35", "eprint_id": 116347, "eprint_status": "archive", "datestamp": "2023-08-22 17:20:28", "lastmod": "2023-10-23 20:15:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Balzer-Christopher", "name": { "family": "Balzer", "given": "Christopher" }, "orcid": "0000-0002-9767-8437" }, { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Wetting behavior of polyelectrolyte complex coacervates on solid surfaces", "ispublished": "pub", "full_text_status": "public", "keywords": "Condensed Matter Physics; General Chemistry", "note": "\u00a9 The Royal Society of Chemistry 2022. \n\nReceived 28th June 2022, Accepted 11th August 2022. \n\nC. B. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0020347. P. Z. acknowledges the financial support provided by the National Natural Science Foundation of China (NSFC grant no. 21803011 and 22073016). Z.-G. W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd. \n\nThere are no conflicts to declare.\n\nSupplemental Material - d2sm00859a1.pdf
", "abstract": "The wetting behavior of complex coacervates underpins their use in many emerging applications of surface science, particularly wet adhesives and coatings. Many factors dictate if a coacervate phase will condense on a solid surface, including solution conditions, the nature of the polymer\u2013substrate interaction, and the underlying supernatant\u2013coacervate bulk phase behavior. In this work, we use a simple inhomogeneous mean-field theory to study the wetting behavior of complex coacervates on solid surfaces both off-coexistence (wetting transitions) and on-coexistence (contact angles). We focus on the effects of salt concentration, the polycation/polyanion surface affinity, and the applied electrostatic potential on the wettability. We find that the coacervate generally wets the surface via a first order wetting transition with second order transitions possible above a surface critical point. Applying an electrostatic potential to a solid surface always improves the surface wettability when the polycation/polyanion\u2013substrate interaction is symmetric. For asymmetric surface affinity, the wettability has a nonmonotonic dependence with the applied potential. We use simple scaling and thermodynamic arguments to explain our results.", "date": "2022-08-11", "date_type": "published", "publication": "Soft Matter", "volume": "18", "number": "34", "publisher": "Royal Society of Chemistry", "pagerange": "6326-6339", "id_number": "CaltechAUTHORS:20220817-896295000", "issn": "1744-683X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220817-896295000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0020347" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21803011" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073016" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1039/d2sm00859a", "primary_object": { "basename": "d2sm00859a1.pdf", "url": "https://authors.library.caltech.edu/records/hr0g9-xps35/files/d2sm00859a1.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Balzer, Christopher; Zhang, Pengfei; et el." }, { "id": "https://authors.library.caltech.edu/records/0dw89-9b687", "eprint_id": 114842, "eprint_status": "archive", "datestamp": "2023-08-22 15:42:34", "lastmod": "2023-10-24 15:13:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chen-Shensheng", "name": { "family": "Chen", "given": "Shensheng" }, "orcid": "0000-0002-6427-935X" }, { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Complexation between Oppositely Charged Polyelectrolytes in Dilute Solution: Effects of Charge Asymmetry", "ispublished": "pub", "full_text_status": "public", "keywords": "Chemical structure, Cluster chemistry, Counterions, Metal clusters, Salts; Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2022 American Chemical Society. \n\nReceived: February 15, 2022; Revised: April 23, 2022; Published: May 13, 2022. \n\nThis research was supported by funding from Hong Kong Quantum AI Lab Ltd. This research used resources of the Center for Functional Nanomaterials (CFN), which is a U.S. Department of Energy Office of Science User Facility, at Brookhaven National Laboratory under Contract DE-SC0012704. P.Z. acknowledges the financial support provided by the National Natural Science Foundation of China (22073016 and 21803011) and the award of Shanghai Dongfang Scholar. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma2c00339_si_001.pdf
", "abstract": "We use dissipative particle dynamics to study polyelectrolyte complexation in dilute solutions under conditions of either chain-length or concentration asymmetry between the polycation and the polyanion, characterized by the macromolecular charge ratio of the minor component to the major component. Our results show that generally the systems form clusters carrying net macromolecular charges. The stoichiometry of these net-charged macromolecular clusters depends on the overall charge asymmetry, and clusters with certain stoichiometry can dominate the cluster population under a wide range of chain-length and concentration asymmetry. The morphology and stability of these net-charged clusters are closely related to their stoichiometry. When the charge ratio reaches a threshold value, the polyions condense into a single large coacervate cluster, signaling the onset of macroscopic coacervation. The threshold value is less for concentration asymmetry systems than for chain-length asymmetry systems at the same salt concentration. This threshold value decreases with added salt, as salt ions cause merging of small clusters into larger ones, eventually leading to the dominance of a single large cluster. This \"salting-out\" phenomenon is followed by a \"salting-in\" behavior, as further addition of salt dissolves the large cluster. The preferred size and composition of the net-charged clusters observed in the simulation highlight the significant role of length and concentration asymmetry on polyelectrolyte complex coacervation and hint at the possibility of a microstructured liquid.", "date": "2022-05-24", "date_type": "published", "publication": "Macromolecules", "volume": "55", "number": "10", "publisher": "American Chemical Society", "pagerange": "3898-3909", "id_number": "CaltechAUTHORS:20220520-388256000", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-388256000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Hong Kong Quantum AI Lab Ltd." }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0012704" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073016" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21803011" }, { "agency": "Shanghai Dongfang Scholar" } ] }, "doi": "10.1021/acs.macromol.2c00339", "primary_object": { "basename": "ma2c00339_si_001.pdf", "url": "https://authors.library.caltech.edu/records/0dw89-9b687/files/ma2c00339_si_001.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Chen, Shensheng; Zhang, Pengfei; et el." }, { "id": "https://authors.library.caltech.edu/records/44r33-mmr92", "eprint_id": 114841, "eprint_status": "archive", "datestamp": "2023-08-22 15:42:26", "lastmod": "2023-10-24 15:12:58", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Supernatant Phase in Polyelectrolyte Complex Coacervation: Cluster Formation, Binodal, and Nucleation", "ispublished": "pub", "full_text_status": "public", "keywords": "Approximation ,Cluster chemistry, Electrostatics, Free energy, Salts; Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2022 American Chemical Society. \n\nReceived: February 15, 2022; Revised: April 13, 2022; Published: May 12, 2022. \n\nThe authors thank Prof. Isamu Kusaka for valuable discussion on the interfacial tension calculation for finite-sized droplets. P.Z. acknowledges the financial support provided by the National Natural Science Foundation of China (22073016 and 21803011) and the award of Shanghai Dongfang Scholar. Z.-G.W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma2c00340_si_001.pdf
", "abstract": "This work studies the structure and thermodynamics of the supernatant phase in polyelectrolyte complex coacervation, a relatively unexplored area. By combining the cluster theory in dilute solution with our recently developed mean-field theory for inhomogeneous polyelectrolyte solutions (Zhang, P.; Wang, Z.-G. Macromolecules 2021, 54, 10994), we systematically investigate the structure of finite-sized clusters formed by oppositely charged polyions in symmetric dilute solutions and how these clusters affect the binodal, spinodal, and nucleation for polyelectrolyte complex coacervation. We find that both the polyion concentration deep inside the cluster and the interfacial tension decrease with increasing the cluster size, reaching their respective bulk coexistence values with corrections inversely proportional to the cluster radius. The polyion concentration in the supernatant phase at coexistence is several orders of magnitude higher than that obtained under the uniform mixing approximation. For most relevant conditions away from the critical point, the supernatant phase consists predominantly of polyion pairs. By examining the nucleation barrier in supersaturated solutions, we can determine a pseudo-spinodal when the barrier is a few multiples of the thermal energy. The location of this pseudo-spinodal is similarly shifted to much higher concentrations than predicted under the uniform mixing approximation. Making the volume approximation for the clusters, we obtain simple analytical expressions for the cluster formation free energy, the modified binodal, and the pseudo-spinodal. In particular, we propose a simple approximate formula for estimating the concentration of the coexisting supernatant phase in terms of the chain length, interfacial tension, and the polyion concentration in the coacervate phase.", "date": "2022-05-24", "date_type": "published", "publication": "Macromolecules", "volume": "55", "number": "10", "publisher": "American Chemical Society", "pagerange": "3910-3923", "id_number": "CaltechAUTHORS:20220520-388254000", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-388254000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "22073016" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21803011" }, { "agency": "Shanghai Dongfang Scholar" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1021/acs.macromol.2c00340", "primary_object": { "basename": "ma2c00340_si_001.pdf", "url": "https://authors.library.caltech.edu/records/44r33-mmr92/files/ma2c00340_si_001.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Zhang, Pengfei and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/xqxp1-1hc78", "eprint_id": 114835, "eprint_status": "archive", "datestamp": "2023-08-22 15:41:48", "lastmod": "2023-10-23 19:52:10", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ye-Benjamin-Bobin", "name": { "family": "Ye", "given": "Benjamin Bobin" }, "orcid": "0000-0003-0253-6311" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "A coarse-grained model of room-temperature ionic liquids between metal electrodes: a molecular dynamics study", "ispublished": "pub", "full_text_status": "public", "keywords": "Physical and Theoretical Chemistry; General Physics and Astronomy", "note": "\u00a9 the Owner Societies 2022. \n\nReceived 11th January 2022, Accepted 27th April 2022. \n\nWe thank Edmond Tingtao Zhou for helpful discussions. This work is supported in part by funding from the Hong Kong Quantum AI Lab Ltd. \n\nThere are no conflicts to declare.\n\nSupplemental Material - d2cp00166g1.pdf
", "abstract": "Recent mean-field theories predict that room-temperature ionic liquid (RTIL) electric double-layer capacitors (EDLCs) undergo a spontaneous surface charge separation (SSCS) with no applied potential. In this study, we construct a coarse-grained molecular model that corresponds to the mean-field models to directly simulate the behavior of RTILs without invoking mean-field approximations. In addition to observing the SSCS transition, we highlight the importance of the image charge interactions and explore the enhanced in-plane ordering on the electrodes, two effects not accounted for by the mean-field theories. By calculating and comparing the differential capacitance for RTILs confined between perfectly conducting and non-metal electrodes, we show that the image charge interactions drastically improve the energy storage properties of RTIL EDLCs.", "date": "2022-05-21", "date_type": "published", "publication": "Physical Chemistry Chemical Physics", "volume": "24", "number": "19", "publisher": "Royal Society of Chemistry", "pagerange": "11573-11584", "id_number": "CaltechAUTHORS:20220520-388214000", "issn": "1463-9076", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-388214000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1039/d2cp00166g", "primary_object": { "basename": "d2cp00166g1.pdf", "url": "https://authors.library.caltech.edu/records/xqxp1-1hc78/files/d2cp00166g1.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Ye, Benjamin Bobin and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/1nbfq-t1r45", "eprint_id": 114843, "eprint_status": "archive", "datestamp": "2023-08-22 15:34:22", "lastmod": "2023-10-24 15:13:05", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhenhua", "name": { "family": "Wang", "given": "Zhenhua" }, "orcid": "0000-0002-6878-6279" }, { "id": "Wang-Ruishu", "name": { "family": "Wang", "given": "Ruishu" } }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Shi-An-Chang", "name": { "family": "Shi", "given": "An-Chang" }, "orcid": "0000-0003-1379-7162" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Mechanisms of Flow-Induced Polymer Translocation", "ispublished": "pub", "full_text_status": "public", "keywords": "Conformation, Fluxes, Monomers, Polymer chains, Polymers; Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2022 American Chemical Society. \n\nReceived 11 February 2022. Revised 11 April 2022. Published online 27 April 2022. Published in issue 10 May 2022. \n\nWe thank Professor Lianwei Li (Shenzhen University) for valuable discussions. This work was supported by the Science Challenge Project (Grant TZ2018004), the National Key R&D Program of China (Grant 2020YFA0713601), the National Natural Science Foundation of China (Grants 21790340 and 22073092), and the Key Research Program of Frontier Sciences, CAS (Grant QYZDY-SSW-SLH027). Additional support for Y.L. was provided by the Youth Innovation Promotion Association of CAS (Grant Y202054). \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma2c00288_si_001.pdf
Supplemental Material - ma2c00288_si_002.mp4
Supplemental Material - ma2c00288_si_003.mp4
Supplemental Material - ma2c00288_si_004.mp4
Supplemental Material - ma2c00288_si_005.mp4
", "abstract": "Flow-induced translocation of linear and ring polymers is studied by using a combination of multiparticle collision dynamics and molecular dynamics. The results show that both end capture and fold capture are present in the capture process of linear chains in weak flows, whereas fold capture becomes dominant in strong flows, resulting in similar behavior for the linear and ring chains in the strong flow regime. For narrow channels, the critical flux decreases with the increase of channel size, which is qualitatively consistent with the prediction by Wu et al.; for large channel sizes (which are still smaller than the polymer size), the critical flux is independent of channel size, in agreement with an earlier prediction by de Gennes et al. The presence of these two scaling regimes indicates that the confined blob exhibits a crossover from free draining to nondraining as the channel size increases. Moreover, we found that the conformation of the polymer exhibits a flow-induced coil\u2013compact\u2013stretch transition, and the transition does not appear to be first order. In addition, we observed that the monomers far from the channel and in the channel exhibit independent dynamics.", "date": "2022-05-10", "date_type": "published", "publication": "Macromolecules", "volume": "55", "number": "9", "publisher": "American Chemical Society", "pagerange": "3602-3612", "id_number": "CaltechAUTHORS:20220520-388263000", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-388263000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Science Challenge Project", "grant_number": "TZ2018004" }, { "agency": "Ministry of Science and Technology (China)", "grant_number": "2020YFA0713601" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21790340" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073092" }, { "agency": "Chinese Academy of Sciences", "grant_number": "QYZDY-SSW-SLH027" }, { "agency": "Chinese Academy of Sciences", "grant_number": "Y202054" } ] }, "doi": "10.1021/acs.macromol.2c00288", "primary_object": { "basename": "ma2c00288_si_001.pdf", "url": "https://authors.library.caltech.edu/records/1nbfq-t1r45/files/ma2c00288_si_001.pdf" }, "related_objects": [ { "basename": "ma2c00288_si_002.mp4", "url": "https://authors.library.caltech.edu/records/1nbfq-t1r45/files/ma2c00288_si_002.mp4" }, { "basename": "ma2c00288_si_003.mp4", "url": "https://authors.library.caltech.edu/records/1nbfq-t1r45/files/ma2c00288_si_003.mp4" }, { "basename": "ma2c00288_si_004.mp4", "url": "https://authors.library.caltech.edu/records/1nbfq-t1r45/files/ma2c00288_si_004.mp4" }, { "basename": "ma2c00288_si_005.mp4", "url": "https://authors.library.caltech.edu/records/1nbfq-t1r45/files/ma2c00288_si_005.mp4" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Wang, Zhenhua; Wang, Ruishu; et el." }, { "id": "https://authors.library.caltech.edu/records/tzepa-avy21", "eprint_id": 114300, "eprint_status": "archive", "datestamp": "2023-10-09 21:00:30", "lastmod": "2023-10-24 16:30:17", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bruch-Dorian", "name": { "family": "Bruch", "given": "Dorian" }, "orcid": "0000-0002-3983-4841" }, { "id": "Balzer-Christopher", "name": { "family": "Balzer", "given": "Christopher" }, "orcid": "0000-0002-9767-8437" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Thermodynamics of electrolyte solutions near charged surfaces: Constant surface charge vs constant surface potential", "ispublished": "pub", "full_text_status": "public", "keywords": "Physical and Theoretical Chemistry; General Physics and Astronomy", "note": "\u00a9 2022 Author(s). Published under an exclusive license by AIP Publishing. \n\nSubmitted: 24 February 2022; Accepted: 07 April 2022; Accepted Manuscript Online: 08 April 2022. \n\nD.B. acknowledges support from the NDSEG Fellowship Program. C.B. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship, under Award No. DE-SC0020347. Z.-G.W. acknowledges financial support from the Hong Kong Quantum AI Lab. \n\nThe authors have no conflicts to disclose. \n\nAuthor Contributions: D.B. and C.B. contributed equally to this work. \n\nData Availability: The data that support the findings of this study are available from the corresponding author upon reasonable request.\n\nPublished - 174704_1_online.pdf
Accepted Version - 174704_1_online-acc.pdf
Submitted - Manuscript.pdf
", "abstract": "Electric double layers are ubiquitous in science and engineering and are of current interest, owing to their applications in the stabilization of colloidal suspensions and as supercapacitors. While the structure and properties of electric double layers in electrolyte solutions near a charged surface are well characterized, there are subtleties in calculating thermodynamic properties from the free energy of a system with charged surfaces. These subtleties arise from the difference in the free energy between systems with constant surface charge and constant surface potential. In this work, we present a systematic, pedagogical framework to properly account for the different specifications on charged bodies in electrolyte solutions. Our approach is fully variational\u2014that is, all free energies, boundary conditions, relevant electrostatic equations, and thermodynamic quantities are systematically derived using variational principles of thermodynamics. We illustrate our approach by considering a simple electrolyte solution between two charged surfaces using the Poisson\u2013Boltzmann theory. Our results highlight the importance of using the proper thermodynamic potential and provide a general framework for calculating thermodynamic properties of electrolyte solutions near charged surfaces. Specifically, we present the calculation of the pressure and the surface tension between two charged surfaces for different boundary conditions, including mixed boundary conditions.", "date": "2022-05-07", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "156", "number": "17", "publisher": "American Institute of Physics", "pagerange": "Art. No. 174704", "id_number": "CaltechAUTHORS:20220414-26162000", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220414-26162000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Defense Science and Engineering Graduate (NDSEG) Fellowship" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0020347" }, { "agency": "Hong Kong Quantum AI Lab" } ] }, "doi": "10.1063/5.0089260", "primary_object": { "basename": "174704_1_online-acc.pdf", "url": "https://authors.library.caltech.edu/records/tzepa-avy21/files/174704_1_online-acc.pdf" }, "related_objects": [ { "basename": "174704_1_online.pdf", "url": "https://authors.library.caltech.edu/records/tzepa-avy21/files/174704_1_online.pdf" }, { "basename": "Manuscript.pdf", "url": "https://authors.library.caltech.edu/records/tzepa-avy21/files/Manuscript.pdf" } ], "resource_type": "article", "pub_year": "2022", "author_list": "Bruch, Dorian; Balzer, Christopher; et el." }, { "id": "https://authors.library.caltech.edu/records/sgj84-47e97", "eprint_id": 114844, "eprint_status": "archive", "datestamp": "2023-08-22 15:31:15", "lastmod": "2023-10-24 15:13:12", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mei-Baicheng", "name": { "family": "Mei", "given": "Baicheng" }, "orcid": "0000-0003-0289-248X" }, { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Local-Average Free Volume Correlates with Dynamics in Glass Formers", "ispublished": "pub", "full_text_status": "public", "keywords": "Amorphous materials, Cluster chemistry, Liquids, Physical and chemical properties, Rearrangement; General Materials Science; Physical and Theoretical Chemistry", "note": "\u00a9 2022 American Chemical Society. \n\nReceived 10 January 2022. Accepted 5 April 2022. Published online 28 April 2022. Published in issue 5 May 2022. \n\nThis work was supported by the National Key R&D Program of China (Grant 2020YFA0713601) and the National Natural Science Foundation of China (Grants 21790340 and 22073092). Additional support for Y.L. was provided by the Youth Innovation Promotion Association of CAS (Grant Y202054). Z.-G.W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - jz2c00072_si_001.pdf
", "abstract": "Glass formers exhibit a pronounced slowdown in dynamics, accompanied by progressive heterogeneity as they approach the glass transition. There is intense debate over whether the dramatic slowdown is caused by dynamical heterogeneity and whether the enhanced dynamical heterogeneity originates from structural causes. However, the connection between dynamical heterogeneity and the spatial distribution of the single-particle free volume (a purely static structural quantity) was found to be rather weak, which raises the question of whether dynamic heterogeneity has a purely structural origin. Here, by introducing the concept of local-average free volume, we present numerical evidence that long-time dynamic heterogeneity shows significantly enhanced correlation with the average local free volume over a length scale of a few neighboring shells. Our results resolve the long-standing controversy about whether free volume plays an important role in particle rearrangements associated with the activated hopping relaxation. The concept of \"local average\" can be applied to other local structural descriptors to better correlate with dynamic heterogeneity in glass-forming liquids.", "date": "2022-05-05", "date_type": "published", "publication": "Journal of Physical Chemistry Letters", "volume": "13", "number": "17", "publisher": "American Chemical Society", "pagerange": "3957-3964", "id_number": "CaltechAUTHORS:20220520-388267000", "issn": "1948-7185", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220520-388267000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Ministry of Science and Technology (China)", "grant_number": "2020YFA0713601" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21790340" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073092" }, { "agency": "Chinese Academy of Sciences", "grant_number": "Y202054" }, { "agency": "Hong Kong Quantum AI Lab Ltd" } ] }, "doi": "10.1021/acs.jpclett.2c00072", "primary_object": { "basename": "jz2c00072_si_001.pdf", "url": "https://authors.library.caltech.edu/records/sgj84-47e97/files/jz2c00072_si_001.pdf" }, "resource_type": "article", "pub_year": "2022", "author_list": "Mei, Baicheng; Zhuang, Bilin; et el." }, { "id": "https://authors.library.caltech.edu/records/qvs2z-ds898", "eprint_id": 112617, "eprint_status": "archive", "datestamp": "2023-08-22 12:56:21", "lastmod": "2023-10-23 22:39:07", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ylitalo-Andrew-S", "name": { "family": "Ylitalo", "given": "Andrew S." }, "orcid": "0000-0003-4086-3508" }, { "id": "Balzer-Christopher", "name": { "family": "Balzer", "given": "Christopher" }, "orcid": "0000-0002-9767-8437" }, { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Electrostatic Correlations and Temperature-Dependent Dielectric Constant Can Model LCST in Polyelectrolyte Complex Coacervation", "ispublished": "pub", "full_text_status": "public", "keywords": "Salts, Electrostatics, Electrical properties, Phase transitions, Polyelectrolytes; Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: September 22, 2021; Revised: November 19, 2021; Published: December 15, 2021. \n\nThe authors express their gratitude to Dr. Yuanchi Ma and Dr. Vivek Prabhu for sharing data and insights from their experimental work and Prof. Joseph Schlenoff for helpful discussion. A.Y. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. C.B. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0020347. P.Z. acknowledges the financial support provided by the National Natural Science Foundation of China (NSFC grant nos. 21803011 and 22073016). Z.-G.W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma1c02000_si_001.pdf
", "abstract": "The ability of polyelectrolytes to condense into a liquidlike, polyelectrolyte-rich phase out of a dilute supernatant phase through complex coacervation has led to fascinating phenomena, such as membraneless organelles and self-assembled capsules for drug delivery. Recent experiments have demonstrated that heating above a lower critical solution temperature (LCST) can drive complex coacervation. Here, we show that a coarse-grained model of electrostatic correlations is sufficient to model an LCST when accounting for the empirical decrease in the dielectric constant of the solvent upon heating. The predictions of the model agree qualitatively with experimental measurements of the compositions of the coexisting coacervate and supernatant phases. The model also achieves modest quantitative agreement with experiments, despite incorporating no other experimental parameters besides the dielectric constant and a fitted length scale. This agreement underscores the important role that can be played by electrostatic correlations in driving complex coacervation above an LCST.", "date": "2021-12-28", "date_type": "published", "publication": "Macromolecules", "volume": "54", "number": "24", "publisher": "American Chemical Society", "pagerange": "11326-11337", "id_number": "CaltechAUTHORS:20211221-866875000", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211221-866875000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1745301" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0020347" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21803011" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073016" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1021/acs.macromol.1c02000", "primary_object": { "basename": "ma1c02000_si_001.pdf", "url": "https://authors.library.caltech.edu/records/qvs2z-ds898/files/ma1c02000_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Ylitalo, Andrew S.; Balzer, Christopher; et el." }, { "id": "https://authors.library.caltech.edu/records/24rq9-5m067", "eprint_id": 112156, "eprint_status": "archive", "datestamp": "2023-08-22 12:53:39", "lastmod": "2023-10-23 20:56:12", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ruan-Yongjin", "name": { "family": "Ruan", "given": "Yongjin" }, "orcid": "0000-0002-8323-4018" }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Shear Banding in Entangled Polymers: Stress Plateau, Banding Location, and Lever Rule", "ispublished": "pub", "full_text_status": "public", "keywords": "Stress, Physical and chemical properties, Equilibrium, Molecular dynamics simulations, Polymers; Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: August 10, 2021; Accepted: November 11, 2021; Published: November 15, 2021. \n\nWe thank Drs. S.-Q. Wang, B. Khomami, and J. Cao for helpful correspondences about their work and thank the anonymous reviewers whose constructive comments have helped improve the presentation of our work. Y. Lu and L. An acknowledge the National Natural Science Foundation of China (grant nos. 21790340, 22073092, 21674113, and 21334007) and the Programs of Chinese Academy of Sciences (grant nos. QYZDY-SSW-SLH027 and YJKYYQ20190084) for financial support. Z.-G. Wang acknowledges financial support from the Hong Kong Quantum AI Lab Ltd. Y. Ruan thanks Dr. R. Graham and Dr. J. Ramirez for helpful discussions on the GLaMM model and Dr. M. Kr\u00f6ger for help with the Z1 code. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - mz1c00518_si_001.pdf
Supplemental Material - mz1c00518_si_002.mp4
Supplemental Material - mz1c00518_si_003.mp4
Supplemental Material - mz1c00518_si_004.pdf
", "abstract": "Using molecular dynamics simulation, we study shear banding of entangled polymer melts under a steady shear. The steady shear stress vs shear rate curve exhibits a plateau spanning nearly two decades of shear rates in which shear banding is observed, and the steady shear stress remains unchanged after switching the shear rates halfway in the range of shear rates within the plateau region. In addition, we find strong correlation in the location of the shear bands between different shear rates starting from the same microstate configurations at equilibrium, which suggests the importance of the inherent structural heterogeneity in the entangled polymer network for shear banding. Furthermore, for the steady shear bands persisting to the longest simulated time of 9.0\u03c4_(d0) (disengagement time), the shear rate in the slow band and the relative proportion of the bands do not change very much with the increase of imposed shear rate, but the shear rate in the fast band increases approximately in proportion to the imposed shear rates, in contradiction to the lever rule.", "date": "2021-12-21", "date_type": "published", "publication": "ACS Macro Letters", "volume": "10", "number": "12", "publisher": "American Chemical Society", "pagerange": "1517-1523", "id_number": "CaltechAUTHORS:20211201-231210047", "issn": "2161-1653", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211201-231210047", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21790340" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073092" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21674113" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21334007" }, { "agency": "Chinese Academy of Sciences", "grant_number": "QYZDY-SSW-SLH027" }, { "agency": "Chinese Academy of Sciences", "grant_number": "YJKYYQ20190084" }, { "agency": "Hong Kong Quantum AI Lab" } ] }, "doi": "10.1021/acsmacrolett.1c00518", "primary_object": { "basename": "mz1c00518_si_004.pdf", "url": "https://authors.library.caltech.edu/records/24rq9-5m067/files/mz1c00518_si_004.pdf" }, "related_objects": [ { "basename": "mz1c00518_si_001.pdf", "url": "https://authors.library.caltech.edu/records/24rq9-5m067/files/mz1c00518_si_001.pdf" }, { "basename": "mz1c00518_si_002.mp4", "url": "https://authors.library.caltech.edu/records/24rq9-5m067/files/mz1c00518_si_002.mp4" }, { "basename": "mz1c00518_si_003.mp4", "url": "https://authors.library.caltech.edu/records/24rq9-5m067/files/mz1c00518_si_003.mp4" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Ruan, Yongjin; Lu, Yuyuan; et el." }, { "id": "https://authors.library.caltech.edu/records/besfy-g9126", "eprint_id": 112152, "eprint_status": "archive", "datestamp": "2023-08-22 12:48:14", "lastmod": "2023-10-23 20:55:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Yuci", "name": { "family": "Xu", "given": "Yuci" }, "orcid": "0000-0001-5163-2807" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Coil-to-Globule Transition in Polymeric Solvents", "ispublished": "pub", "full_text_status": "public", "keywords": "Thickness, Free energy, Solvents, Phase transitions, Polymers; Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2021 American Chemical Society. \n\nReceived 19 August 2021. Revised 1 November 2021. Published online 17 November 2021. \n\nY.X. gratefully acknowledges the funding support from the National Natural Science Foundation of China (grants 21973051) and the Chinese Scholarship Council. Z.-G.W. acknowledges the financial support from the Hong Kong Quantum AI Lab Ltd. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma1c01748_si_001.pdf
", "abstract": "We study the coil-to-globule (C\u2013G) transition of a test polymer of chain length N1 in a polymeric solvent of chain length N using the self-consistent field theory. For short-chain solvents, the C\u2013G transition point is given by (\u03c7N)_(tr)\u20131/2 \u223c (pN)^(3/4)N\u2081^(\u20131/2), consistent with an extended Lifshitz theory, where p = b\u00b2/v_m^(2/3) is the stiffness parameter. However, for long-chain solvents, the C\u2013G transition becomes strongly first order, with the transition point given by (\u03c7N)_(tr)\u20131/2 \u223c pNN\u2081^(\u20132/3). A scaling analysis suggests that the transition point for any chain length combination is a universal function of the scaling variable x \u2261 (pN)^(3/2)/N\u2081, which has the clear interpretation as the ratio between the pervaded volume of the solvent chain and the physical volume of the test chain and that a crossover between the two transition scenarios occurs at x \u223c 1. Furthermore, when properly nondimensionalized, the density profile in the globule state and the center density and the interfacial thickness of the globule at the transition also exhibit universal behavior. For both the short-chain and long-chain solvent cases, the C\u2013G transition corresponds to the point when the interfacial thickness of the globule becomes comparable to the core size.", "date": "2021-12-14", "date_type": "published", "publication": "Macromolecules", "volume": "54", "number": "23", "publisher": "American Chemical Society", "pagerange": "10984-10993", "id_number": "CaltechAUTHORS:20211201-231208714", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211201-231208714", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21973051" }, { "agency": "China Scholarship Council" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1021/acs.macromol.1c01748", "primary_object": { "basename": "ma1c01748_si_001.pdf", "url": "https://authors.library.caltech.edu/records/besfy-g9126/files/ma1c01748_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Xu, Yuci and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/zeqr3-91h35", "eprint_id": 112153, "eprint_status": "archive", "datestamp": "2023-08-22 12:48:23", "lastmod": "2023-10-23 20:55:57", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Interfacial Structure and Tension of Polyelectrolyte Complex Coacervates", "ispublished": "pub", "full_text_status": "public", "keywords": "Salts, Interfaces, Electrostatics, Monomers, Polyelectrolytes; Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2021 American Chemical Society. \n\nReceived 28 August 2021. Revised 21 October 2021. Published online 15 November 2021. \n\nP.Z. acknowledges the financial support provided by the National Natural Science Foundation of China (21803011 and 22073016) and the award of Shanghai Dongfang Scholar. Z.-G.W. acknowledges the financial support from the Hong Kong Quantum AI Lab Ltd. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma1c01809_si_001.pdf
", "abstract": "We develop a simple inhomogeneous mean-field theory to study the interfacial structure and tension of polyelectrolyte complex coacervates in equilibrium with a supernatant solution. Our theory treats the electrostatic correlation by combining the Debye\u2013H\u00fcckel theory with the first-order thermodynamic perturbation theory within the local density approximation, and incorporates the conformation entropy contribution for both polyions using Lifshitz's ground-state dominance approximation. Using this theory, we systematically examine the interfacial properties of both symmetric and concentration-asymmetric coacervates. The interfacial tension \u03b3 is generally rather low, on the order of 1 mN/m or less. For asymmetric coacervates, an intricate electric double layer forms in the interfacial region, which can even contain several oscillations under certain conditions. The interfacial tension generally decreases with increasing the stoichiometric asymmetry, the added-salt concentration, and the initial polymer concentration of the mixture. We further find that the interfacial tension can be quantitatively related to the degree of phase separation S, where S is the Euclidean distance in composition between the two coexisting phases. In particular, we find that \u03b3 as a function of S for different concentration asymmetries collapses approximately to two master curves, which merge together and follow \u03b3 \u223c S\u00b3 for small S.", "date": "2021-12-14", "date_type": "published", "publication": "Macromolecules", "volume": "54", "number": "23", "publisher": "American Chemical Society", "pagerange": "10994-11007", "id_number": "CaltechAUTHORS:20211201-231209762", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20211201-231209762", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21803011" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073016" }, { "agency": "Hong Kong Quantum AI Lab Ltd." }, { "agency": "Shanghai Dongfang Scholar" } ] }, "doi": "10.1021/acs.macromol.1c01809", "primary_object": { "basename": "ma1c01809_si_001.pdf", "url": "https://authors.library.caltech.edu/records/zeqr3-91h35/files/ma1c01809_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Zhang, Pengfei and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/t8q8b-k5589", "eprint_id": 109767, "eprint_status": "archive", "datestamp": "2023-08-22 10:35:54", "lastmod": "2023-10-23 18:09:39", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lian-Zengju", "name": { "family": "Lian", "given": "Zengju" }, "orcid": "0000-0002-0233-8297" }, { "id": "Chao-Huikuan", "name": { "family": "Chao", "given": "Huikuan" }, "orcid": "0000-0001-9930-3586" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of Confinement and Ion Adsorption in Ionic Liquid Supercapacitors with Nanoporous Electrodes", "ispublished": "pub", "full_text_status": "public", "keywords": "ionic-liquid supercapacitors; energy storage; ion correlations; ion adsorption; confinement effects; surface transition; nanoporous", "note": "\u00a9 2021 American Chemical Society. \n\nReceived 24 March 2021. Accepted 22 June 2021. Published online 6 July 2021. \n\nZ.L. acknowledges financial support from the Fundamental Research Funds for the Provincial Universities of Zhejiang (No.SJLY2020006), Foundation of Zhejiang Educational Committee (No.Y20173 7177), and Natural Science Foundation of Ningbo (No.202003N4106). She also acknowledges support from the K.C.Wong Magna Fund in Ningbo University. Z.-G.W. acknowledges financial support from the Hong Kong Quantum AI Lab Ltd. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - nn1c02506_si_001.pdf
", "abstract": "We investigate the effects of pore size and ion adsorption on the room-temperature ionic liquid capacitor with nanoporous electrodes, with a focus on optimizing the capacitance and energy storage. Using a recently developed modified BSK model accounting for both ion correlations and nonelectrostatic interactions, we find that ion crowding proximate to the electrode surface induced by the spontaneous charge separation due to strong ion correlations is responsible for the anomalous increase in the capacitance with decreasing pore sizes observed in experiments. Reducing the strength of ion correlations increases the capacitance and suppresses the anomalous size dependence. For a given pore size, the capacitance peak diverges when the ion correlation strength \u03b1 reaches a critical value, \u03b1_(sc,L). The capacitance peak shifts to smaller pore size as \u03b1 decreases because of rapid decrease of \u03b1_(sc,L) with decreasing pore size. Asymmetric preferential ion adsorption is shown to lead to significantly enhanced energy storage close to the transition point for any pore sizes. For a given correlation strength, the energy storage is optimal at a pore size where \u03b1 = \u03b1_(sc,L).", "date": "2021-07-27", "date_type": "published", "publication": "ACS Nano", "volume": "15", "number": "7", "publisher": "American Chemical Society", "pagerange": "11724-11733", "id_number": "CaltechAUTHORS:20210709-222308605", "issn": "1936-0851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210709-222308605", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Fundamental Research Funds for the Provincial Universities of Zhejiang", "grant_number": "SJLY2020006" }, { "agency": "Foundation of Zhejiang Educational Committee", "grant_number": "Y20173 7177" }, { "agency": "Natural Science Foundation of Ningbo", "grant_number": "202003N4106" }, { "agency": "Ningbo University" }, { "agency": "Hong Kong Quantum AI Lab Ltd." } ] }, "doi": "10.1021/acsnano.1c02506", "primary_object": { "basename": "nn1c02506_si_001.pdf", "url": "https://authors.library.caltech.edu/records/t8q8b-k5589/files/nn1c02506_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Lian, Zengju; Chao, Huikuan; et el." }, { "id": "https://authors.library.caltech.edu/records/516tm-9hz54", "eprint_id": 110049, "eprint_status": "archive", "datestamp": "2023-08-20 04:16:59", "lastmod": "2023-10-23 18:16:10", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Balzer-Christopher", "name": { "family": "Balzer", "given": "Christopher" }, "orcid": "0000-0002-9767-8437" }, { "id": "Qing-Leying", "name": { "family": "Qing", "given": "Leying" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Preferential Ion Adsorption in Blue Energy Applications", "ispublished": "pub", "full_text_status": "public", "keywords": "capacitive mixing, alternative energy, density functional theory, preferential adsorption, electric double layer,\nthermodynamics", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: February 25, 2021; Revised: June 17, 2021; Published: July 7, 2021. \n\nC.B. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship, under award number DE-SC0020347. L.Q. is grateful to the China Scholarship Council. \n\nAuthor Contributions: C.B. and L.Q. contributed equally. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - sc1c01326_si_001.pdf
", "abstract": "The available blue energy (or salinity gradient energy) in a capacitive double-layer expansion (CDLE) process is directly determined by the interplay between adsorption and release of ions from the electrodes at different salt concentrations. In this work, we explore the effect of asymmetric preferential ion adsorption at nanoporous anode and cathode surfaces as a means to enhance the available blue energy. We find that preferential adsorption can not only enhance the available energy output but also shift the supplied potential difference in the CDLE process toward the \"spontaneous voltage\". We determine the maximum available energy for the CDLE process as a function of the pore size and the degree of asymmetric adsorption. In the mixing of river water and saltwater, we find that preferential adsorption can give as much as 10% more available energy compared to indifferent electrode surfaces.", "date": "2021-07-19", "date_type": "published", "publication": "ACS Sustainable Chemistry & Engineering", "volume": "9", "number": "28", "publisher": "American Chemical Society", "pagerange": "9230-9239", "id_number": "CaltechAUTHORS:20210728-155607490", "issn": "2168-0485", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210728-155607490", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0020347" }, { "agency": "China Scholarship Council" } ] }, "doi": "10.1021/acssuschemeng.1c01326", "primary_object": { "basename": "sc1c01326_si_001.pdf", "url": "https://authors.library.caltech.edu/records/516tm-9hz54/files/sc1c01326_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Balzer, Christopher; Qing, Leying; et el." }, { "id": "https://authors.library.caltech.edu/records/9m6ds-p8h34", "eprint_id": 108982, "eprint_status": "archive", "datestamp": "2023-08-22 09:51:36", "lastmod": "2023-10-23 17:29:05", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Son-Chang-Yun", "name": { "family": "Son", "given": "Chang Yun" }, "orcid": "0000-0002-0784-6565" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Image-charge effects on ion adsorption near aqueous interfaces", "ispublished": "pub", "full_text_status": "public", "keywords": "ion adsorption; aqueous interfaces; electrochemical cell; image-charge\nmethod; polarization", "note": "\u00a9 2021 National Academy of Sciences. Published under the PNAS license. \n\nEdited by Monica Olvera de la Cruz, Northwestern University, Evanston, IL, and approved March 16, 2021 (received for review October 1, 2020). \n\nWe thank the Dow Chemical Company for funding and for permission to publish the results. We also thank the NVIDIA Corporation for the donation of the Titan Xp GPU card used for this research. \n\nData Availability: All study data are included in the article and/or SI Appendix. \n\nAuthor contributions: C.Y.S. and Z.-G.W. designed research; C.Y.S. performed research; C.Y.S. and Z.-G.W. analyzed data; and C.Y.S. and Z.-G.W. wrote the paper. \n\nThe authors declare no competing interest. \n\nThis article is a PNAS Direct Submission. \n\nThis article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2020615118/-/DCSupplemental.\n\nPublished - e2020615118.full.pdf
Supplemental Material - pnas.2020615118.sapp.pdf
", "abstract": "Electrostatic interactions near surfaces and interfaces are ubiquitous in many fields of science. Continuum electrostatics predicts that ions will be attracted to conducting electrodes but repelled by surfaces with lower dielectric constant than the solvent. However, several recent studies found that certain \"chaotropic\" ions have similar adsorption behavior at air/water and graphene/water interfaces. Here we systematically study the effect of polarization of the surface, the solvent, and solutes on the adsorption of ions onto the electrode surfaces using molecular dynamics simulation. An efficient method is developed to treat an electrolyte system between two parallel conducting surfaces by exploiting the mirror-expanded symmetry of the exact image-charge solution. With neutral surfaces, the image interactions induced by the solvent dipoles and ions largely cancel each other, resulting in no significant net differences in the ion adsorption profile regardless of the surface polarity. Under an external electric field, the adsorption of ions is strongly affected by the surface polarization, such that the charge separation across the electrolyte and the capacitance of the cell is greatly enhanced with a conducting surface over a low-dielectric-constant surface. While the extent of ion adsorption is highly dependent on the electrolyte model (the polarizability of solvent and solutes, as well as the van der Waals radii), we find the effect of surface polarization on ion adsorption is consistent throughout different electrolyte models.", "date": "2021-05-11", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "118", "number": "19", "publisher": "National Academy of Sciences", "pagerange": "Art. No. e2020615118", "id_number": "CaltechAUTHORS:20210506-081218514", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210506-081218514", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" } ] }, "doi": "10.1073/pnas.2020615118", "pmcid": "PMC8126851", "primary_object": { "basename": "e2020615118.full.pdf", "url": "https://authors.library.caltech.edu/records/9m6ds-p8h34/files/e2020615118.full.pdf" }, "related_objects": [ { "basename": "pnas.2020615118.sapp.pdf", "url": "https://authors.library.caltech.edu/records/9m6ds-p8h34/files/pnas.2020615118.sapp.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Son, Chang Yun and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/4d893-3bc32", "eprint_id": 108873, "eprint_status": "archive", "datestamp": "2023-08-20 03:13:10", "lastmod": "2023-10-23 17:23:14", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Balzer-Christopher", "name": { "family": "Balzer", "given": "Christopher" }, "orcid": "0000-0002-9767-8437" }, { "id": "Jiang-Jian", "name": { "family": "Jiang", "given": "Jian" }, "orcid": "0000-0003-4171-5275" }, { "id": "Marson-Ryan-L", "name": { "family": "Marson", "given": "Ryan L." } }, { "id": "Ginzburg-Valeriy-V", "name": { "family": "Ginzburg", "given": "Valeriy V." }, "orcid": "0000-0002-2775-5492" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nonelectrostatic Adsorption of Polyelectrolytes and Mediated Interactions between Solid Surfaces", "ispublished": "pub", "full_text_status": "public", "keywords": "Salts, Electrostatics, Adsorption, Polyelectrolytes, Polymers", "note": "\u00a9 2021 American Chemical Society. \n\nReceived: January 15, 2021; Revised: April 14, 2021; Published: April 29, 2021. \n\nThe Dow Chemical Company is acknowledged for partly funding the work and permission to publish the results. C.B. is supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Department of Energy Computational Science Graduate Fellowship under Award Number DE-SC0020347. We thank Dr. Chang Yun Son, Dr. Anthony Van Dyk, Dr. Thomas Kalantar, and Dr. Christopher Tucker for helpful discussions. \n\nAuthor Contributions. C.B. and J.J. contributed equally. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - la1c00139_si_001.pdf
", "abstract": "Polymer-mediated interaction between two solid surfaces is directly connected to the properties of the adsorbed polymer layers. Nonelectrostatic interactions with a surface can significantly impact the adsorption of polyelectrolytes to charged surfaces. We use a classical density functional theory to study the effect of various polyelectrolyte solution properties on the adsorption and interaction between two like-charged surfaces. Our results show that nonelectrostatic interactions not only enhance polyelectrolyte adsorption but can also result in qualitatively different salt effects with respect to the adsorbed amount. In particular, we observe decreasing, increasing, and a previously unreported nonmonotonic behavior in the adsorbed amount of polymer with added salt under the conditions studied, although the nonmonotonic regime only occurs for a narrow range in the parameter space. With sufficient nonelectrostatic adsorption, the adsorbed polymer layers produce a long-range repulsive barrier that is strong enough to overcome dispersive interactions that cause surfaces to attract. Concurrently, a short-range bridging attraction is observed when the two polyelectrolyte layers span both the surfaces. Both the repulsive barrier and bridging attraction depend on the charge density of the polymer backbone and the bulk salt concentration but not on the chain length in the semidilute regime studied.", "date": "2021-05-11", "date_type": "published", "publication": "Langmuir", "volume": "37", "number": "18", "publisher": "American Chemical Society", "pagerange": "5483-5493", "id_number": "CaltechAUTHORS:20210429-132053968", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210429-132053968", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-SC0020347" } ] }, "doi": "10.1021/acs.langmuir.1c00139", "primary_object": { "basename": "la1c00139_si_001.pdf", "url": "https://authors.library.caltech.edu/records/4d893-3bc32/files/la1c00139_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Balzer, Christopher; Jiang, Jian; et el." }, { "id": "https://authors.library.caltech.edu/records/ndjwc-r0427", "eprint_id": 108065, "eprint_status": "archive", "datestamp": "2023-08-20 01:49:53", "lastmod": "2023-10-23 16:26:34", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Ramanauskaite-Gabriele", "name": { "family": "Ramanauskaite", "given": "Gabriele" } }, { "id": "Koa-Zhao-Yuan", "name": { "family": "Koa", "given": "Zhao Yuan" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Like dissolves like: A first-principles theory for predicting liquid miscibility and mixture dielectric constant", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY). \n\nSubmitted 11 September 2020; Accepted 24 December 2020; Published 12 February 2021. \n\nWe thank D. Tirrell, I. Nakamura, R. Wang, K. Shen, P. Zhang, N. Alsaifi, and J. Jiang for helpful discussions throughout this work. We also thank the anonymous reviewers whose comments have helped to improve this work. Funding: This work was supported by the Yale-NUS College Start-Up Grant and the Yale-NUS College Summer Research Programme. Acknowledgement is also made to the donors of the American Chemical Society Petroleum Research Fund (53404-ND5) for partial support of this research. Author contributions: B.Z. and Z.-G.W. conceived the research. B.Z. formulated the theory. B.Z., G.R., and Z.Y.K. performed the numerical calculations and analyzed the data. B.Z. and Z.-G.W. wrote the manuscript. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors.\n\nPublished - eabe7275.full.pdf
Supplemental Material - abe7275_SM.pdf
", "abstract": "Liquid mixtures are ubiquitous. Miscibility and dielectric constant are fundamental properties that govern the applications of liquid mixtures. However, despite their importance, miscibility is usually predicted qualitatively based on the vaguely defined polarity of the liquids, and the dielectric constant of the mixture is modeled by introducing mixing rules. Here, we develop a first-principles theory for polar liquid mixtures using a statistical field approach, without resorting to mixing rules. With this theory, we obtain simple expressions for the mixture's dielectric constant and free energy of mixing. The dielectric constant predicted by this theory agrees well with measured data for simple binary mixtures. On the basis of the derived free energy of mixing, we can construct a miscibility map in the parameter space of the dielectric constant and molar volume for each liquid. The predicted miscibility shows remarkable agreement with known data, thus providing a quantitative basis for the empirical \"like-dissolves-like\" rule.", "date": "2021-02-12", "date_type": "published", "publication": "Science Advances", "volume": "7", "number": "7", "publisher": "American Association for the Advancement of Science", "pagerange": "Art. No. eabe7275", "id_number": "CaltechAUTHORS:20210216-121335555", "issn": "2375-2548", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210216-121335555", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Yale-NUS College" }, { "agency": "American Chemical Society Petroleum Research Fund", "grant_number": "53404-ND5" } ] }, "doi": "10.1126/sciadv.abe7275", "pmcid": "PMC7880597", "primary_object": { "basename": "abe7275_SM.pdf", "url": "https://authors.library.caltech.edu/records/ndjwc-r0427/files/abe7275_SM.pdf" }, "related_objects": [ { "basename": "eabe7275.full.pdf", "url": "https://authors.library.caltech.edu/records/ndjwc-r0427/files/eabe7275.full.pdf" } ], "resource_type": "article", "pub_year": "2021", "author_list": "Zhuang, Bilin; Ramanauskaite, Gabriele; et el." }, { "id": "https://authors.library.caltech.edu/records/84dx9-ept12", "eprint_id": 107417, "eprint_status": "archive", "datestamp": "2023-08-20 01:28:44", "lastmod": "2023-10-23 15:52:14", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Qing-Leying", "name": { "family": "Qing", "given": "Leying" } }, { "id": "Zhao-Shuangliang", "name": { "family": "Zhao", "given": "Shuangliang" }, "orcid": "0000-0002-9547-4860" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Surface Charge Density in Electrical Double Layer Capacitors with Nanoscale Cathode\u2013Anode Separation", "ispublished": "pub", "full_text_status": "public", "keywords": "Equilibrium, Electrical properties, Electrodes, Ions, Surface charge", "note": "\u00a9 2021 American Chemical Society. \n\nReceived 14 October 2020. Revised 17 December 2020. Published online 6 January 2021. \n\nPublished as part of The Journal of Physical Chemistry virtual special issue \"Carol K. Hall Festschrift\". \n\nL.Q. is grateful to the China Scholarship Council for supporting her visit at the California Institute of Technology. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - jp0c09332_si_001.pdf
", "abstract": "Using a dynamic density functional theory, we study the charging dynamics, the final equilibrium structure, and the energy storage in an electrical double layer capacitor with nanoscale cathode\u2013anode separation in a slit geometry. We derive a simple expression for the surface charge density that naturally separates the effects of the charge polarization due to the ions from those due to the polarization of the dielectric medium and allows a more intuitive understanding of how the ion distribution within the cell affects the surface charge density. We find that charge neutrality in the half-cell does not hold during the dynamic charging process for any cathode\u2013anode separation, and also does not hold at the final equilibrium state for small separations. Therefore, the charge accumulation in the half-cell in general does not equal the surface charge density. The relationships between the surface charge density and the charge accumulation within the half-cell are systematically investigated by tuning the electrolyte concentration, cathode\u2013anode separation, and applied voltage. For high electrolyte concentrations, we observe charge inversion at which the charge accumulation exceeds the surface charge at special values of the separation. In addition, we find that the energy density has a maximum at intermediate electrolyte concentrations for a high applied voltage.", "date": "2021-01-21", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "125", "number": "2", "publisher": "American Chemical Society", "pagerange": "625-636", "id_number": "CaltechAUTHORS:20210112-091401503", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210112-091401503", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "China Scholarship Council" } ] }, "doi": "10.1021/acs.jpcb.0c09332", "primary_object": { "basename": "jp0c09332_si_001.pdf", "url": "https://authors.library.caltech.edu/records/84dx9-ept12/files/jp0c09332_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Qing, Leying; Zhao, Shuangliang; et el." }, { "id": "https://authors.library.caltech.edu/records/qdgdn-nt003", "eprint_id": 107494, "eprint_status": "archive", "datestamp": "2023-08-20 01:28:11", "lastmod": "2023-10-23 15:57:04", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Minglun", "name": { "family": "Li", "given": "Minglun" }, "orcid": "0000-0002-1286-6915" }, { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Salt-Induced Liquid\u2013Liquid Phase Separation: Combined Experimental and Theoretical Investigation of Water\u2013Acetonitrile\u2013Salt Mixtures", "ispublished": "pub", "full_text_status": "public", "keywords": "Salts, Free energy, Ions, Mixtures, Hydration", "note": "\u00a9 2021 American Chemical Society. \n\nReceived 1 September 2020. Published online 8 January 2021. \n\nY.L. and L.A. acknowledge the National Natural Science Foundation of China (Grant Nos. 21790340 and 21674113) and the Programs of Chinese Academy of Sciences (Grant No. QYZDY-SSW-SLH027) for financial support. Y.L. also acknowledges the Key Science and Technology Project of Jilin Province (Grant No. 20200504001YY) for financial support. We thank Dr. Pengfei Zhang (Donghua University) for helpful discussions, and we thank the anonymous reviewers whose comments have helped improve the presentation of our work. \n\nAuthor Contributions. M.L. and B.Z. contributed equally to this work. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ja0c09420_si_001.pdf
", "abstract": "Salt-induced liquid\u2013liquid phase separation in liquid mixtures is a common phenomenon in nature and in various applications, such as in separation and extraction of chemicals. Here, we present results of a systematic investigation of the phase behaviors in water\u2013acetonitrile\u2013salt mixtures using a combination of experiment and theory. We obtain complete ternary phase diagrams for nine representative salts in water\u2013acetonitrile mixtures by cloud point and component analysis. We construct a thermodynamic free energy model by accounting for the nonideal mixing of the liquids, ion hydration, electrostatic interactions, and Born energy. Our theory yields phase diagrams in good agreement with the experimental data. By comparing the contributions due to the electrostatic interaction, Born energy, and hydration, we find that hydration is the main driving force for the liquid\u2013liquid separation and is a major contributor to the specific ion effects. Our theory highlights the important role of entropy in the hydration driving force. We discuss the implications of our findings in the context of salting-out assisted liquid\u2013liquid extraction and make suggestions for selecting salt ions to optimize the separation performance.", "date": "2021-01-20", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "143", "number": "2", "publisher": "American Chemical Society", "pagerange": "773-784", "id_number": "CaltechAUTHORS:20210114-164619058", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210114-164619058", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21790340" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21674113" }, { "agency": "Chinese Academy of Sciences", "grant_number": "QYZDY-SSW-SLH027" }, { "agency": "Key Science and Technology Project of Jilin Province", "grant_number": "20200504001YY" } ] }, "doi": "10.1021/jacs.0c09420", "primary_object": { "basename": "ja0c09420_si_001.pdf", "url": "https://authors.library.caltech.edu/records/qdgdn-nt003/files/ja0c09420_si_001.pdf" }, "resource_type": "article", "pub_year": "2021", "author_list": "Li, Minglun; Zhuang, Bilin; et el." }, { "id": "https://authors.library.caltech.edu/records/ytq0e-mkm07", "eprint_id": 106683, "eprint_status": "archive", "datestamp": "2023-08-20 00:48:25", "lastmod": "2023-10-20 23:41:36", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Alsaifi-Nayef-M", "name": { "family": "Alsaifi", "given": "Nayef M." }, "orcid": "0000-0003-3232-6411" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Revisiting the \u0398 Point", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Chemical Society. \n\nReceived: June 4, 2020; Revised: September 27, 2020; Published: November 16, 2020. \n\nThis work was conducted jointly by King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia, and California Institute of Technology (Caltech) under a collaborative research program in catalysis. The authors gratefully acknowledge the support provided by KFUPM and Caltech. Pengfei Zhang also acknowledges the financial support provided by the National Natural Science Foundation of China (21803011 and 22073016). \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma0c01317_si_001.pdf
", "abstract": "Using the first-order perturbation theory, we compute the osmotic second and third virial coefficients, the mean-square end-to-end distance \u27e8R_e\u00b2\u27e9, and the mean-square radius of gyration \u27e8R_g\u00b2\u27e9 of a polymer near the \u0398 point. Our model is based on the discrete Gaussian chain model and includes a square-gradient term accounting for the finite-range interaction (characterized by \u03ba), in addition to the usual monomer second and third virial coefficients (characterized by v and w, respectively). The use of the discrete model avoids the divergence problems encountered in previous studies using the continuous model. Our study identifies four special temperatures in the \u0398 regime: the temperature \u0398_N where the osmotic second virial coefficient vanishes, the critical temperature \u0398_N^(cr) for phase separation, and two compensation temperatures \u0398_N^((e)) and \u0398_N^((g)) at which \u27e8R_e\u00b2\u27e9 and \u27e8R_g\u00b2\u27e9 reach their respective ideal values. In the infinite chain-length limit N \u2192 \u221e, all of these four temperatures approach \u0398\u221e, the \u0398 temperature for the infinitely long chain. These temperatures differ from each other by terms of order N^(\u20131/2). In general, these temperatures follow the order \u0398_N > \u0398_N^(cr) and \u0398_N > \u0398_N^((e)) > \u0398_N^((g)). Furthermore, \u0398_N > \u0398\u221e, in agreement with the result obtained by Khokhlov some time ago. On the other hand, depending on the ratio w/\u03bab, \u0398\u221e can be higher than \u0398_N^((e)) (for w/\u03bab < 9.45), lower than \u0398_N^((g)) (for w/\u03bab > 11.63), or in between \u0398_N^((e)) and \u0398_N^((g)) (for 9.45 < w/\u03bab < 11.63). \u0398_N^(cr) can be either higher or lower than \u0398\u221e depending on whether w/b\u2076 is larger or smaller than 0.574. From the order of these temperatures, we conclude that the chain is mostly expanded relative to the ideal chain at its \u0398_N. However, at \u0398\u221e, the chain can be either expanded or contracted, depending on the relative position of \u0398\u221e with respect to \u0398_N^((e)) and \u0398_N^((g)) and depending on whether the chain dimension is measured by \u27e8R_e\u00b2\u27e9 or \u27e8R_g\u00b2\u27e9.", "date": "2020-12-08", "date_type": "published", "publication": "Macromolecules", "volume": "53", "number": "23", "publisher": "American Chemical Society", "pagerange": "10409-10420", "id_number": "CaltechAUTHORS:20201116-151452336", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201116-151452336", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "Caltech" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21803011" }, { "agency": "National Natural Science Foundation of China", "grant_number": "22073016" } ] }, "doi": "10.1021/acs.macromol.0c01317", "primary_object": { "basename": "ma0c01317_si_001.pdf", "url": "https://authors.library.caltech.edu/records/ytq0e-mkm07/files/ma0c01317_si_001.pdf" }, "resource_type": "article", "pub_year": "2020", "author_list": "Zhang, Pengfei; Alsaifi, Nayef M.; et el." }, { "id": "https://authors.library.caltech.edu/records/zzcmw-x8t37", "eprint_id": 105343, "eprint_status": "archive", "datestamp": "2023-08-19 23:21:07", "lastmod": "2023-10-20 21:52:52", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Son-Chang-Yun", "name": { "family": "Son", "given": "Chang Yun" }, "orcid": "0000-0002-0784-6565" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Ion transport in small-molecule and polymer electrolytes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 AIP Publishing. \n\nSubmitted: 4 June 2020 \u2022 Accepted: 12 August 2020 \u2022 Published Online: 9 September 2020. \n\nZ.-G.W. thanks Umi Yamamoto, Brett Savoie, Michael Webb, Tom Miller, and Nitash Balsara for useful discussions on ion transport over the years. \n\nDATA AVAILABILITY. All data except those in Fig. 8(b) were from published literature, with the references given in the figure captions. Figure 8(b) was generated from the data in Fig. 8(a) (taken from Ref. 177) using Eq. (4.2). These data are available from the authors upon request.\n\nPublished - 5.0016163.pdf
", "abstract": "Solid-state polymer electrolytes and high-concentration liquid electrolytes, such as water-in-salt electrolytes and ionic liquids, are emerging materials to replace the flammable organic electrolytes widely used in industrial lithium-ion batteries. Extensive efforts have been made to understand the ion transport mechanisms and optimize the ion transport properties. This perspective reviews the current understanding of the ion transport and polymer dynamics in liquid and polymer electrolytes, comparing the similarities and differences in the two types of electrolytes. Combining recent experimental and theoretical findings, we attempt to connect and explain ion transport mechanisms in different types of small-molecule and polymer electrolytes from a theoretical perspective, linking the macroscopic transport coefficients to the microscopic, molecular properties such as the solvation environment of the ions, salt concentration, solvent/polymer molecular weight, ion pairing, and correlated ion motion. We emphasize universal features in the ion transport and polymer dynamics by highlighting the relevant time and length scales. Several outstanding questions and anticipated developments for electrolyte design are discussed, including the negative transference number, control of ion transport through precision synthesis, and development of predictive multiscale modeling approaches.", "date": "2020-09-14", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "153", "number": "10", "publisher": "American Institute of Physics", "pagerange": "Art. No. 100903", "id_number": "CaltechAUTHORS:20200911-133136426", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200911-133136426", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1063/5.0016163", "primary_object": { "basename": "5.0016163.pdf", "url": "https://authors.library.caltech.edu/records/zzcmw-x8t37/files/5.0016163.pdf" }, "resource_type": "article", "pub_year": "2020", "author_list": "Son, Chang Yun and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/wrhyc-4yt03", "eprint_id": 101217, "eprint_status": "archive", "datestamp": "2023-08-19 20:28:44", "lastmod": "2023-10-19 22:33:04", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Chao-Huikuan", "name": { "family": "Chao", "given": "Huikuan" }, "orcid": "0000-0001-9930-3586" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of Surface Transition and Adsorption on Ionic Liquid Capacitors", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Chemical Society. \n\nReceived: January 3, 2020; Accepted: February 10, 2020; Published: February 10, 2020. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - jz0c00023_si_001.pdf
", "abstract": "Room-temperature ionic liquids (RTILs) are synthetic electrolytes with electrochemical stability superior to that of conventional aqueous-based electrolytes, allowing a significantly enlarged electrochemical window for application as capacitors. In this study, we propose a variant of an existing RTIL model for solvent-free RTILs, accounting for both ion\u2013ion correlations and nonelectrostatic interactions. Using this model, we explore the phenomenon of spontaneous surface charge separation in RTIL capacitors and find that this transition is a common feature for realistic choices of the model parameters in most RTILs. In addition, we investigate the effects of asymmetric preferential ion adsorption on this charge separation transition and find that proximity of the transition in this case can result in greatly enhanced energy storage. Our work suggests that differential chemical treatment of electrodes can be a simple and useful means for optimizing energy storage in RTIL capacitors.", "date": "2020-03-05", "date_type": "published", "publication": "Journal of Physical Chemistry Letters", "volume": "11", "number": "5", "publisher": "American Chemical Society", "pagerange": "1767-1772", "id_number": "CaltechAUTHORS:20200211-074528495", "issn": "1948-7185", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200211-074528495", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1021/acs.jpclett.0c00023", "primary_object": { "basename": "jz0c00023_si_001.pdf", "url": "https://authors.library.caltech.edu/records/wrhyc-4yt03/files/jz0c00023_si_001.pdf" }, "resource_type": "article", "pub_year": "2020", "author_list": "Chao, Huikuan and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/fhhvj-1qb05", "eprint_id": 100756, "eprint_status": "archive", "datestamp": "2023-08-19 19:23:40", "lastmod": "2023-10-18 21:50:24", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Omar-A-K", "name": { "family": "Omar", "given": "Ahmad K." }, "orcid": "0000-0002-6404-7612" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Brady-J-F", "name": { "family": "Brady", "given": "John F." }, "orcid": "0000-0001-5817-9128" } ] }, "title": "Microscopic origins of the swim pressure and the anomalous surface tension of active matter", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2020 American Physical Society. \n\nReceived 6 June 2019; published 16 January 2020. \n\nA.K.O. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469 and an HHMI Gilliam Fellowship. J.F.B. acknowledges support by the National Science Foundation under Grant No. CBET-1803662.\n\nPublished - PhysRevE.101.012604.pdf
Submitted - 1912.11727.pdf
Supplemental Material - SM_omar_surface_tension_2019_PRE.pdf
Supplemental Material - dropletdynamics.mp4
Supplemental Material - slabpreparation.mp4
", "abstract": "The unique pressure exerted by active particles\u2014the \"swim\" pressure\u2014has proven to be a useful quantity in explaining many of the seemingly confounding behaviors of active particles. However, its use has also resulted in some puzzling findings including an extremely negative surface tension between phase separated active particles. Here, we demonstrate that this contradiction stems from the fact that the swim pressure is not a true pressure. At a boundary or interface, the reduction in particle swimming generates a net active force density\u2014an entirely self-generated body force. The pressure at the boundary, which was previously identified as the swim pressure, is in fact an elevated (relative to the bulk) value of the traditional particle pressure that is generated by this interfacial force density. Recognizing this unique mechanism for stress generation allows us to define a much more physically plausible surface tension. We clarify the utility of the swim pressure as an \"equivalent pressure\" (analogous to those defined from electrostatic and gravitational body forces) and the conditions in which this concept can be appropriately applied.", "date": "2020-01", "date_type": "published", "publication": "Physical Review E", "volume": "101", "number": "1", "publisher": "American Physical Society", "pagerange": "Art. No. 012604", "id_number": "CaltechAUTHORS:20200116-094602547", "issn": "2470-0045", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200116-094602547", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1144469" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "NSF", "grant_number": "CBET-1803662" } ] }, "doi": "10.1103/physreve.101.012604", "primary_object": { "basename": "1912.11727.pdf", "url": "https://authors.library.caltech.edu/records/fhhvj-1qb05/files/1912.11727.pdf" }, "related_objects": [ { "basename": "PhysRevE.101.012604.pdf", "url": "https://authors.library.caltech.edu/records/fhhvj-1qb05/files/PhysRevE.101.012604.pdf" }, { "basename": "SM_omar_surface_tension_2019_PRE.pdf", "url": "https://authors.library.caltech.edu/records/fhhvj-1qb05/files/SM_omar_surface_tension_2019_PRE.pdf" }, { "basename": "dropletdynamics.mp4", "url": "https://authors.library.caltech.edu/records/fhhvj-1qb05/files/dropletdynamics.mp4" }, { "basename": "slabpreparation.mp4", "url": "https://authors.library.caltech.edu/records/fhhvj-1qb05/files/slabpreparation.mp4" } ], "resource_type": "article", "pub_year": "2020", "author_list": "Omar, Ahmad K.; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/a701g-cde63", "eprint_id": 100136, "eprint_status": "archive", "datestamp": "2023-08-19 19:06:17", "lastmod": "2023-10-18 19:07:14", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Jiang-Jian", "name": { "family": "Jiang", "given": "Jian" } }, { "id": "Ginzburg-Valeriy-V", "name": { "family": "Ginzburg", "given": "Valeriy V." }, "orcid": "0000-0002-2775-5492" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "On the origin of oscillatory interactions between surfaces mediated by polyelectrolyte solution", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 Published under license by AIP Publishing. \n\nSubmitted: 5 August 2019; Accepted: 13 November 2019; Published Online: 2 December 2019. \n\nThe Dow Chemical Company is acknowledged for funding and for permission to publish the results.\n\nPublished - 1.5123172.pdf
", "abstract": "We use a numerical implementation of polymer classical density functional theory with an incompressibility condition to study the system consisting of nonadsorbing polyelectrolytes confined by two planar surfaces and quantify the effective interaction between the two planar surfaces as a function of the polyelectrolyte and salt concentrations. Our results indicate that for the uncharged surfaces (and weakly charged surfaces), the effective interaction primarily consists of a short-range attraction due to the depletion followed by repulsion due to the electric double layer overlapping and electrostatic correlations. For salt-free and low salt concentration systems, the magnitude of the repulsion barrier is determined by the overlap between the electric double layers, while at relatively high salt concentrations, the magnitude of the repulsion barrier is determined by the electrostatic correlations. Due to the competition between the electric double layer and the electrostatic correlations, the magnitude of the repulsion barrier varies nonmonotonically. In contrast, a mean-field Poisson-Boltzmann treatment of the electrostatics predicts a monotonically decreasing repulsion barrier with increasing salt concentration. At moderate salt concentrations, our theory predicts oscillatory interaction profiles. A comparison with the mean-field Poisson-Boltzmann treatment of electrostatics suggests that the oscillations are due primarily to electrostatic correlations.", "date": "2019-12-07", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "151", "number": "21", "publisher": "American Institute of Physics", "pagerange": "Art. No. 214901", "id_number": "CaltechAUTHORS:20191202-105354237", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191202-105354237", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" } ] }, "doi": "10.1063/1.5123172", "primary_object": { "basename": "1.5123172.pdf", "url": "https://authors.library.caltech.edu/records/a701g-cde63/files/1.5123172.pdf" }, "resource_type": "article", "pub_year": "2019", "author_list": "Jiang, Jian; Ginzburg, Valeriy V.; et el." }, { "id": "https://authors.library.caltech.edu/records/trayg-tbx11", "eprint_id": 99861, "eprint_status": "archive", "datestamp": "2023-08-19 18:31:51", "lastmod": "2023-10-18 18:52:43", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Mei-Baicheng", "name": { "family": "Mei", "given": "Baicheng" }, "orcid": "0000-0003-0289-248X" }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Two-step relaxation and the breakdown of the Stokes-Einstein relation in glass-forming liquids", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Physical Society. \n\nReceived 30 August 2019; published 15 November 2019. \n\nThis work was supported by the Science Challenge Project (Grant No. TZ2018004), the National Natural Science Foundation of China (Grants No. 21674113 and No. 21790340), the Key Research Program of Frontier Sciences, CAS (Grant No. QYZDY-SSW-SLH027), the International Partnership Program of CAS (Grant No. 121522KYSB20160015), and Jilin Scientific and Technological Development Program (Grant No. 20180519001JH). Y.L. acknowledges the Youth Innovation Promotion Association of CAS (Grant No. 2016204) for financial support.\n\nPublished - PhysRevE.100.052607.pdf
", "abstract": "It is well known that glass-forming liquids exhibit a number of anomalous dynamical phenomena, most notably a two-step relaxation in the self-intermediate scattering function and the breakdown of the Stokes-Einstein (SE) relation, as they are cooled toward the glass transition temperature. While these phenomena are generally ascribed to dynamic heterogeneity, specifically to the presence of slow- and fast-moving particles, a quantitative elucidation of the two-step relaxation and the violation of the SE relation in terms of these concepts has not been successful. In this work, we propose a classification of particles according to the rank order of their displacements (from an arbitrarily defined origin of time), and we divide the particles into long-distance (LD), medium-distance, and short-distance (SD) traveling particle groups. Using molecular-dynamics simulation data of the Kob-Andersen model, we show quantitatively that the LD group is responsible for the fast relaxation in the two-step relaxation process in the intermediate scattering function, while the SD group gives rise to the slow (\u03b1) relaxation. Furthermore, our analysis reveals that \u03c4_\u03b1 is controlled by the SD group, while the ensemble-averaged diffusion coefficient D is controlled by both the LD and SD groups. The combination of these two features provides a natural explanation for the breakdown in the SE relation at low temperature. In addition, we find that the \u03b1-relaxation time, \u03c4_\u03b1, of the overall system is related to the relaxation time of the LD particles, \u03c4_(LD), as \u03c4_\u03b1 = \u03c4\u2080exp(\u03a9\u03c4_(LD)/k_BT).", "date": "2019-11", "date_type": "published", "publication": "Physical Review E", "volume": "100", "number": "5", "publisher": "American Physical Society", "pagerange": "Art. No. 052607", "id_number": "CaltechAUTHORS:20191115-074621027", "issn": "2470-0045", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191115-074621027", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Science Challenge Project", "grant_number": "TZ2018004" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21674113" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21790340" }, { "agency": "Chinese Academy of Sciences", "grant_number": "QYZDY-SSW-SLH027" }, { "agency": "Chinese Academy of Sciences", "grant_number": "121522KYSB20160015" }, { "agency": "Jilin Scientific and Technological Development Program", "grant_number": "20180519001JH" }, { "agency": "Chinese Academy of Sciences", "grant_number": "2016204" } ] }, "doi": "10.1103/physreve.100.052607", "primary_object": { "basename": "PhysRevE.100.052607.pdf", "url": "https://authors.library.caltech.edu/records/trayg-tbx11/files/PhysRevE.100.052607.pdf" }, "resource_type": "article", "pub_year": "2019", "author_list": "Mei, Baicheng; Lu, Yuyuan; et el." }, { "id": "https://authors.library.caltech.edu/records/0hjjc-kj831", "eprint_id": 96519, "eprint_status": "archive", "datestamp": "2023-08-19 16:43:02", "lastmod": "2023-10-20 21:15:43", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Preska-Steinberg-A", "name": { "family": "Preska Steinberg", "given": "Asher" }, "orcid": "0000-0002-8694-7224" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Ismagilov-R-F", "name": { "family": "Ismagilov", "given": "Rustem F." }, "orcid": "0000-0002-3680-4399" } ] }, "title": "Food Polyelectrolytes Compress the Colonic Mucus Hydrogel by a Donnan Mechanism", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. \n\nReceived: March 29, 2019; Revised: May 23, 2019; Published: June 19, 2019. \n\nThis work was supported in part by Army Research Office (ARO) Multidisciplinary University Research Initiative (MURI) contract no. W911NF-17-1-0402, the Jacobs Institute for Molecular Engineering for Medicine, the Center for Environmental Microbial Interactions (CEMI), an NSF Graduate Research Fellowship DGE-144469 (to A.P.S.), and a Caldwell CEMI Graduate Fellowship (to A.P.S.). We acknowledge Michael Porter for useful discussion and providing feedback on the manuscript; Andres Collazo and Caltech's Beckman Institute Biological Imaging Facility, the Caltech Office of Laboratory Animal Resources, and the Caltech veterinary technicians for technical support; Justin Rolando for providing microparticles; and Natasha Shelby for contributions to writing and editing this manuscript. \n\nAuthor Contributions: A.P.S. and R.F.I. designed the research; A.P.S. performed the research; A.P.S. analyzed the data. Z.-G.W. guided the theoretical analysis. All authors wrote the paper. \n\nThe authors declare the following competing financial interest(s): The technology described in this publication is the subject of a patent application filed by Caltech.\n\nPublished - acs.biomac.9b00442.pdf
Supplemental Material - bm9b00442_si_001.pdf
Supplemental Material - bm9b00442_si_002.zip
", "abstract": "Systems consisting of a polyelectrolyte solution in contact with a cross-linked polyelectrolyte network are ubiquitous (e.g., biofilms, drug-delivering hydrogels, and mammalian extracellular matrices), yet the underlying physics governing these interactions is not well understood. Here, we find that carboxymethyl cellulose, a polyelectrolyte commonly found in processed foods and associated with inflammation and obesity, compresses the colonic mucus hydrogel (a key regulator of host\u2013microbe interactions and a protective barrier) in mice. The extent of this polyelectrolyte-induced compression is enhanced by the degree of polymer negative charge. Through animal experiments and numerical calculations, we find that this phenomenon can be described by a Donnan mechanism. Further, the observed behavior can be quantitatively described by a simple, one-parameter model. This work suggests that polymer charge should be considered when developing food products because of its potential role in modulating the protective properties of colonic mucus.", "date": "2019-07-08", "date_type": "published", "publication": "Biomacromolecules", "volume": "20", "number": "7", "publisher": "American Chemical Society", "pagerange": "2675-2683", "id_number": "CaltechAUTHORS:20190619-091518942", "issn": "1525-7797", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190619-091518942", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Army Research Office (ARO)", "grant_number": "W911NF-17-1-0402" }, { "agency": "Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "Caltech Center for Environmental Microbial Interactions (CEMI)" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-144469" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" }, { "id": "Caltech-Center-for-Environmental-Microbial-Interactions-(CEMI)" } ] }, "doi": "10.1021/acs.biomac.9b00442", "primary_object": { "basename": "bm9b00442_si_001.pdf", "url": "https://authors.library.caltech.edu/records/0hjjc-kj831/files/bm9b00442_si_001.pdf" }, "related_objects": [ { "basename": "bm9b00442_si_002.zip", "url": "https://authors.library.caltech.edu/records/0hjjc-kj831/files/bm9b00442_si_002.zip" }, { "basename": "acs.biomac.9b00442.pdf", "url": "https://authors.library.caltech.edu/records/0hjjc-kj831/files/acs.biomac.9b00442.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Preska Steinberg, Asher; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/tcctp-f8f33", "eprint_id": 95731, "eprint_status": "archive", "datestamp": "2023-08-19 16:16:58", "lastmod": "2023-10-20 20:30:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ruan-Yongjin", "name": { "family": "Ruan", "given": "Yongjin" }, "orcid": "0000-0002-8323-4018" }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nonlinear Rheological Behaviors in Polymer Melts after Step Shear", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2019 American Chemical Society. \n\nReceived: February 25, 2019; Revised: April 30, 2019; Published: May 22, 2019. \n\nThis work was supported by the National Natural Science Foundation of China (grant nos. 21790340, 21334007, and 21674113), the Key Research Program of Frontier Sciences, CAS (grant no. QYZDY-SSW-SLH027), and Jilin Scientific and Technological Development Program (grant no. 20180519001JH). Y.L. acknowledges the Youth Innovation Promotion Association of CAS (grant no. 2016204) for financial support. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma9b00392_si_001.pdf
Supplemental Material - ma9b00392_si_002.mpg
Supplemental Material - ma9b00392_si_003.mpg
", "abstract": "Using molecular dynamics simulation, we investigate the evolution of chain conformation, stress relaxation, and fracture for a polymer melt between two walls after step shear. We find that the characteristic overlap time for the reduced relaxation moduli and the time that the stretched primitive chain retracts to its equilibrium length are both much longer than the Rouse time. Importantly, we observe significant fracture-like flow after shear cessation. While there is considerable randomness in the location of the fracture plane and the magnitude of displacement from sample to sample, our analysis suggests that the randomness is not due to thermal noise, but may reflect inherent structural and dynamic heterogeneity in the entangled polymer network.", "date": "2019-06-11", "date_type": "published", "publication": "Macromolecules", "volume": "52", "number": "11", "publisher": "American Chemical Society", "pagerange": "4103-4110", "id_number": "CaltechAUTHORS:20190523-094613725", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190523-094613725", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21790340" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21334007" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21674113" }, { "agency": "Chinese Academy of Sciences", "grant_number": "QYZDY-SSW-SLH027" }, { "agency": "Jilin Scientific and Technological Development Program", "grant_number": "20180519001JH" }, { "agency": "Chinese Academy of Sciences", "grant_number": "2016204" } ] }, "doi": "10.1021/acs.macromol.9b00392", "primary_object": { "basename": "ma9b00392_si_002.mpg", "url": "https://authors.library.caltech.edu/records/tcctp-f8f33/files/ma9b00392_si_002.mpg" }, "related_objects": [ { "basename": "ma9b00392_si_003.mpg", "url": "https://authors.library.caltech.edu/records/tcctp-f8f33/files/ma9b00392_si_003.mpg" }, { "basename": "ma9b00392_si_001.pdf", "url": "https://authors.library.caltech.edu/records/tcctp-f8f33/files/ma9b00392_si_001.pdf" } ], "resource_type": "article", "pub_year": "2019", "author_list": "Ruan, Yongjin; Lu, Yuyuan; et el." }, { "id": "https://authors.library.caltech.edu/records/84j52-vjw17", "eprint_id": 92236, "eprint_status": "archive", "datestamp": "2023-08-19 13:59:36", "lastmod": "2023-10-20 00:07:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Alsaifi-N-M", "name": { "family": "Alsaifi", "given": "Nayef M." }, "orcid": "0000-0003-3232-6411" }, { "id": "Alkhater-M", "name": { "family": "Alkhater", "given": "Mohammed" } }, { "id": "Binous-H", "name": { "family": "Binous", "given": "Housam" } }, { "id": "Al Aslani-I", "name": { "family": "Al Aslani", "given": "Isa" } }, { "id": "Alsunni-Y", "name": { "family": "Alsunni", "given": "Yousef" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nonphysical Behavior in Several Statistical Mechanically Based Equations of State", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2019 American Chemical Society. \n\nReceived: September 23, 2018; Revised: December 31, 2018; Accepted: January 4, 2019; Published: January 11, 2019. \n\nThe authors gratefully acknowledge the support of King Fahd University of Petroleum & Minerals through the grant to KFUPM-Caltech Research in Catalysis. \n\nThe authors declare no competing financial interest.", "abstract": "In this work, we utilize bifurcation diagrams to study the role of mathematical artifacts in deteriorating the physical behavior in statistical mechanically based equations of state of pure fluids. We study the impact of common empirical approximations usually employed to overcome some of the mathematical and physical challenges such as the parametrization of mean field models or pair correlations functions at contact. The proposed diagrams elucidate how the reduced molar volume bifurcates with the variation of temperature at constant pressure. We generate bifurcation diagrams for the modified van der Waals equation of state (EOS) of Poole et al, SAFT-VR Mie, Soft-SAFT, CK-SAFT, and the original SAFT EOSs for spherical and nonspherical molecules. We find that the bifurcation diagram can serve as a useful schematic tool to reveal the unphysical PVT behavior, demonstrate the existence of physical and spurious two-phase separation regions, and illustrate how the number of molar volume roots vary with temperatures. Our method shows that the presence of unphysical branches can cause spurious two-phase separation regions and create erroneous behavior in the stability limit of vapor\u2013liquid equilibrium. We demonstrate that the existence of customary and spurious phase envelopes is accompanied by S-shaped behavior in the volume-temperature bifurcation diagrams. The study reveals that none of the SAFT models is free from producing unphysical behavior. While the SAFT-VR Mie EOS exhibits solid\u2013liquid-like behavior for nonspherical molecules, the CK-SAFT EOS shows liquid\u2013liquid demixing behavior for spherical and nonspherical compounds. For the soft-SAFT EOS, three different two-phase separation regions are observed in addition to the common vapor\u2013liquid phase separation region.", "date": "2019-01-23", "date_type": "published", "publication": "Industrial & Engineering Chemistry Research", "volume": "58", "number": "3", "publisher": "American Chemical Society", "pagerange": "1382-1395", "id_number": "CaltechAUTHORS:20190114-073829851", "issn": "0888-5885", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190114-073829851", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" } ] }, "doi": "10.1021/acs.iecr.8b04656", "resource_type": "article", "pub_year": "2019", "author_list": "Alsaifi, Nayef M.; Alkhater, Mohammed; et el." }, { "id": "https://authors.library.caltech.edu/records/111kd-n8f63", "eprint_id": 91978, "eprint_status": "archive", "datestamp": "2023-08-19 13:58:40", "lastmod": "2023-10-19 23:52:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Omar-A-K", "name": { "family": "Omar", "given": "Ahmad K." }, "orcid": "0000-0002-6404-7612" }, { "id": "Wu-Yanze", "name": { "family": "Wu", "given": "Yanze" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Brady-J-F", "name": { "family": "Brady", "given": "John F." }, "orcid": "0000-0001-5817-9128" } ] }, "title": "Swimming to Stability: Structural and Dynamical Control via Active Doping", "ispublished": "pub", "full_text_status": "public", "keywords": "dynamic assembly, active matter, colloidal gel, depletion, Brownian dynamics", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: September 28, 2018; Accepted: December 28, 2018; Published: December 28, 2018. \n\nA.K.O. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469 and an HHMI Gilliam Fellowship. Y.W. acknowledges the Caltech SURF program and support by the Talent Training Program in Basic Science of the Ministry of Education of the People's Republic of China. J.F.B. acknowledges support by the National Science Foundation under Grant No. CBET-1437570. \n\nThe authors declare no competing financial interest.\n\nSubmitted - 1902.02423.pdf
", "abstract": "External fields can decidedly alter the free energy landscape of soft materials and can be exploited as a powerful tool for the assembly of targeted nanostructures and colloidal materials. Here, we use computer simulations to demonstrate that nonequilibrium internal fields or forces\u2014forces that are generated by driven components within a system\u2014in the form of active particles can precisely modulate the dynamical free energy landscape of a model soft material, a colloidal gel. Embedding a small fraction of active particles within a gel can provide a unique pathway for the dynamically frustrated network to circumvent the kinetic barriers associated with reaching a lower free energy state through thermal fluctuations alone. Moreover, by carefully tuning the active particle properties (the propulsive swim force and persistence length) in comparison to those of the gel, the active particles may induce depletion-like forces between the constituent particles of the gel despite there being no geometric size asymmetry between the particles. These resulting forces can rapidly push the system toward disparate regions of phase space. Intriguingly, the state of the material can be altered by tuning macroscopic transport properties such as the solvent viscosity. Our findings highlight the potential wide-ranging structural and kinetic control facilitated by varying the dynamical properties of a remarkably small fraction of driven particles embedded in a host material.", "date": "2019-01-22", "date_type": "published", "publication": "ACS Nano", "volume": "13", "number": "1", "publisher": "American Chemical Society", "pagerange": "560-572", "id_number": "CaltechAUTHORS:20190102-092234094", "issn": "1936-0851", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190102-092234094", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1144469" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" }, { "agency": "Ministry of Education (China)" }, { "agency": "NSF", "grant_number": "CBET-1437570" } ] }, "doi": "10.1021/acsnano.8b07421", "primary_object": { "basename": "1902.02423.pdf", "url": "https://authors.library.caltech.edu/records/111kd-n8f63/files/1902.02423.pdf" }, "resource_type": "article", "pub_year": "2019", "author_list": "Omar, Ahmad K.; Wu, Yanze; et el." }, { "id": "https://authors.library.caltech.edu/records/pm3gc-jx894", "eprint_id": 90073, "eprint_status": "archive", "datestamp": "2023-09-22 22:50:07", "lastmod": "2023-10-23 23:29:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rapp-Peter-B", "name": { "family": "Rapp", "given": "Peter B." }, "orcid": "0000-0002-9586-2126" }, { "id": "Omar-Ahmad-K", "name": { "family": "Omar", "given": "Ahmad K." }, "orcid": "0000-0002-6404-7612" }, { "id": "Silverman-Bradley-R", "name": { "family": "Silverman", "given": "Bradley R." }, "orcid": "0000-0002-9256-8941" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Tirrell-D-A", "name": { "family": "Tirrell", "given": "David A." }, "orcid": "0000-0003-3175-4596" } ] }, "title": "Mechanisms of diffusion in associative polymer networks: evidence for chain hopping", "ispublished": "pub", "full_text_status": "public", "keywords": "diffusion, mechanism, hopping, entropy, binding, hydrogel, FRAP", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: July 25, 2018; Published: October 1, 2018.\n\nWe thank Andres Collazo of the Caltech Beckman Imaging Facility for expert assistance with acquisition of FRAP data. This work was supported by grant number DMR-1506483 from the Biomaterials Program of the U.S. National Science Foundation. A.K.O. acknowledges support from the National Science Foundation Graduate Research Fellowship under grant no. DGE-1144469 and an HHMI Gilliam Fellowship. B.R.S. acknowledges support from NIH predoctoral training grant 1T32GM112592 and from the Rosen Center for Bioengineering.\n\nP.B.R. and A.K.O. contributed equally to this work.\n\nThe authors declare no competing financial interest.\n\nAccepted Version - nihms-1792560.pdf
Supplemental Material - ja8b07908_si_001.pdf
", "abstract": "Networks assembled by reversible association of telechelic polymers constitute a common class of soft materials. Various mechanisms of chain migration in associative networks have been proposed; yet there remains little quantitative experimental data to discriminate among them. Proposed mechanisms for chain migration include multichain aggregate diffusion as well as single-chain mechanisms such as \"walking\" and \"hopping\", wherein diffusion is achieved by either partial (\"walking\") or complete (\"hopping\") disengagement of the associated chain segments. Here, we provide evidence that hopping can dominate the effective diffusion of chains in associative networks due to a strong entropic penalty for bridge formation imposed by local network structure; chains become conformationally restricted upon association with two or more spatially separated binding sites. This restriction decreases the effective binding strength of chains with multiple associative domains, thereby increasing the probability that a chain will hop. For telechelic chains this manifests as binding asymmetry, wherein the first association is effectively stronger than the second. We derive a simple thermodynamic model that predicts the fraction of chains that are free to hop as a function of tunable molecular and network properties. A large set of self-diffusivity measurements on a series of model associative polymers finds good agreement with this model.", "date": "2018-10-31", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "140", "number": "43", "publisher": "American Chemical Society", "pagerange": "14185-14194", "id_number": "CaltechAUTHORS:20181001-131358075", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181001-131358075", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-1506483" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1144469" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "NIH Predoctoral Fellowship", "grant_number": "1T32GM112592" }, { "agency": "Donna and Benjamin M. Rosen Bioengineering Center" } ] }, "local_group": { "items": [ { "id": "Rosen-Bioengineering-Center" } ] }, "doi": "10.1021/jacs.8b07908", "pmcid": "PMC8997312", "primary_object": { "basename": "ja8b07908_si_001.pdf", "url": "https://authors.library.caltech.edu/records/pm3gc-jx894/files/ja8b07908_si_001.pdf" }, "related_objects": [ { "basename": "nihms-1792560.pdf", "url": "https://authors.library.caltech.edu/records/pm3gc-jx894/files/nihms-1792560.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Rapp, Peter B.; Omar, Ahmad K.; et el." }, { "id": "https://authors.library.caltech.edu/records/0g3jk-mmw04", "eprint_id": 87604, "eprint_status": "archive", "datestamp": "2023-09-15 05:56:29", "lastmod": "2023-10-23 21:22:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Alsaifi-N-M", "name": { "family": "Alsaifi", "given": "Nayef M." }, "orcid": "0000-0003-3232-6411" }, { "id": "Wu-Jianzhong", "name": { "family": "Wu", "given": "Jianzhong" }, "orcid": "0000-0002-4582-5941" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Polyelectrolyte complex coacervation: Effects of concentration asymmetry", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 AIP Publishing LLC. \n\n(Received 11 March 2018; accepted 23 April 2018; published online 6 July 2018) \n\nSPECIAL TOPIC: CHEMICAL PHYSICS OF CHARGED MACROMOLECULES \n\nThis work was conducted jointly by King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia and California Institute of Technology (Caltech) under a collaborative research program in catalysis. The authors gratefully acknowledge the support provided by KFUPM and Caltech. J.W. acknowledges partial financial support from the U.S. National Science Foundation (Grant No. NSF-CBET-8200852353).\n\nPublished - 1.5028524.pdf
Supplemental Material - .listing
Supplemental Material - SI_ComplexCoacervation.pdf
", "abstract": "Using a simple liquid-state theory, we study the phase behaviors of concentration-asymmetric mixtures of polycation and polyanion solutions. We construct a three-dimensional (3D) phase diagram in terms of the concentrations of the three independent charged components: polycation, polyanion, and small cation (p_(P^+) \u2212 p_(P^\u2212) \u2212 p_+), for a given Bjerrum length. This phase diagram yields rich and complex phase-separation scenarios. To illustrate, we sequentially examine the following three systems that are directly relevant to experiments: a symmetric mixture, an asymmetric mixture with one type of small ions, and an asymmetric mixture with both types of small ions. We re-express the information in the 3D phase diagram using three experimentally more easily controllable parameters\u2014the asymmetry factor r, the initial extra-salt concentration p_(s,0), and the initial polyelectrolyte (PE) concentration p_(P,0) of both solutions prior to mixing. We construct three reduced phase diagrams in the p_(P,0) \u2212 r, r \u2212 p_(s,0), and p_(s,0) \u2212 p_(P,0) planes, respectively, and examine the evolution of the volume fraction of the coexisting phases, concentration of the PE and small-ion species in each phase, and the Galvani potential \u03a8_G, as functions of these experimental controlling parameters. We rationalize our findings in terms of the key thermodynamic factors, namely, the translational entropy of the small ions, the electrostatic correlation energy, and the requirement for charge neutrality.", "date": "2018-10-28", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "149", "number": "16", "publisher": "American Institute of Physics", "pagerange": "Art. No. 163303", "id_number": "CaltechAUTHORS:20180706-133157000", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180706-133157000", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CBET-8200852353" } ] }, "doi": "10.1063/1.5028524", "primary_object": { "basename": "1.5028524.pdf", "url": "https://authors.library.caltech.edu/records/0g3jk-mmw04/files/1.5028524.pdf" }, "related_objects": [ { "basename": "SI_ComplexCoacervation.pdf", "url": "https://authors.library.caltech.edu/records/0g3jk-mmw04/files/SI_ComplexCoacervation.pdf" }, { "basename": ".listing", "url": "https://authors.library.caltech.edu/records/0g3jk-mmw04/files/.listing" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Zhang, Pengfei; Alsaifi, Nayef M.; et el." }, { "id": "https://authors.library.caltech.edu/records/0hgjk-t8h02", "eprint_id": 89956, "eprint_status": "archive", "datestamp": "2023-08-19 11:37:09", "lastmod": "2023-10-18 23:06:54", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Statistical field theory for polar fluids", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 Published by AIP Publishing. \n\nReceived 28 June 2018; accepted 3 September 2018; published online 26 September 2018. \n\nWe thank Issei Nakamura, Rui Wang, Kevin Shen, Jian Jiang, Nayef Alsaifi, and Pengfei Zhang for helpful discussions. B.Z. gratefully acknowledges the support by an A-STAR fellowship. Acknowledgement is also made to the donors of the American Chemical Society Petroleum Research Fund for partial support of this research.\n\nPublished - 1.5046511.pdf
Supplemental Material - DRGF_supplementary_v2.pdf
", "abstract": "Using a variational field-theoretic approach, we derive a theory for polar fluids. The theory naturally accounts for the reaction field without resorting to the cavity construct and leads to a simple formula for the dielectric constant in terms of the molecular dipole moment and density. We apply our formula to calculate the dielectric constants of nonpolarizable liquid models for more than a hundred small molecules without using any adjustable parameters. Our formula predicts dielectric constants of these nonpolarizable liquid models more accurately than the Onsager theory and previous field-theoretic dielectric theories, as demonstrated by the closer agreement to the simulation results. The general theory also yields the free energy, which can describe the response of polar fluids under applied electric fields.", "date": "2018-09-28", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "149", "number": "12", "publisher": "American Institute of Physics", "pagerange": "Art. No. 124108", "id_number": "CaltechAUTHORS:20180926-103709613", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180926-103709613", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Agency for Science, Technology and Research (A*STAR)" }, { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1063/1.5046511", "primary_object": { "basename": "1.5046511.pdf", "url": "https://authors.library.caltech.edu/records/0hgjk-t8h02/files/1.5046511.pdf" }, "related_objects": [ { "basename": "DRGF_supplementary_v2.pdf", "url": "https://authors.library.caltech.edu/records/0hgjk-t8h02/files/DRGF_supplementary_v2.pdf" } ], "resource_type": "article", "pub_year": "2018", "author_list": "Zhuang, Bilin and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/s6egs-mce48", "eprint_id": 87967, "eprint_status": "archive", "datestamp": "2023-08-19 11:04:38", "lastmod": "2023-10-18 21:34:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" }, "orcid": "0000-0002-4226-1394" }, { "id": "Shen-Kevin", "name": { "family": "Shen", "given": "Kevin" }, "orcid": "0000-0001-9715-7474" }, { "id": "Alsaifi-N-M", "name": { "family": "Alsaifi", "given": "Nayef M." }, "orcid": "0000-0003-3232-6411" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Salt Partitioning in Complex Coacervation of Symmetric Polyelectrolytes", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: April 9, 2018. Revised: June 30, 2018. Publication Date (Web): July 18, 2018. \n\nWe thank Matthew Tirrell for sending ref (29) prior to publication. This work was conducted jointly by King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia, and California Institute of Technology (Caltech) under a collaborative research program in catalysis. Additional support was provided by the Jacobs Institute for Molecular Engineering in Medicine (JIMEM). \n\nThe authors declare no competing financial interest.", "abstract": "We perform a general thermodynamic analysis for the\nsalt partitioning behavior in the coexisting phases for symmetric\nmixtures of polycation and polyanion solutions. We find that salt\npartitioning is determined by the competition between two factors\ninvolving the ratio of the polyelectrolyte concentration in the coacervate phase to that in the supernatant phase and the difference in the exchange excess chemical potential \u0394\u03bc_(ex) -- the excess chemical potential difference between PE segments and small ions --\n between the coexisting phases. The enrichment of salt ions in the coacervate phase predicted by the Voorn\u2212Overbeek theory is shown to arise from its neglect of chain connectivity in the excess free energy which results in \u0394\u03bc_(ex) = 0 under all conditions. We argue that chain connectivity in general leads to a finite value of \u0394\u03bcex, which decreases with increasing PE concentration. Explicit calculations using theories that include the chain connectivity correlations -- a simple liquid-state theory and a renormalized Gaussian fluctuation theory -- show nonmonotonic behavior of the salt-partitioning coefficient (the ratio of salt ion concentration in the coacervate phase to that in the supernatant phase): it is larger than 1 at very low salt concentrations, reaches a minimum at some intermediate salt concentration, and approaches 1 at the critical point. This behavior is consistent with recent computer simulation and experimental results.", "date": "2018-08-14", "date_type": "published", "publication": "Macromolecules", "volume": "51", "number": "15", "publisher": "American Chemical Society", "pagerange": "5586-5593", "id_number": "CaltechAUTHORS:20180718-144046071", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180718-144046071", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "Caltech" }, { "agency": "Jacobs Institute for Molecular Engineering for Medicine" } ] }, "doi": "10.1021/acs.macromol.8b00726", "resource_type": "article", "pub_year": "2018", "author_list": "Zhang, Pengfei; Shen, Kevin; et el." }, { "id": "https://authors.library.caltech.edu/records/vhqn1-tcb28", "eprint_id": 87440, "eprint_status": "archive", "datestamp": "2023-08-19 10:37:21", "lastmod": "2023-10-18 21:10:58", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Jiang-Jian", "name": { "family": "Jiang", "given": "Jian" } }, { "id": "Ginzburg-V-V", "name": { "family": "Ginzburg", "given": "Valeriy V." }, "orcid": "0000-0002-2775-5492" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Density functional theory for charged fluids", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2018 The Royal Society of Chemistry. \n\nThe article was received on 21 Mar 2018, accepted on 12 Jun 2018 and first published on 13 Jun 2018. \n\nThe Dow Chemical Company is acknowledged for funding and for permission to publish the results. We thank Prof. Lutful Bari Bhuiyan for providing the simulation data in Fig. 1.", "abstract": "An improved density functional theory (DFT) for an inhomogeneous charged system (including electrolyte and/or polyelectrolyte) is proposed based on fundamental measure theory, thermodynamic perturbation theory and mean-spherical approximation. Our DFT combines the existing treatment of hard-sphere contributions using fundamental measure theory (FMT) with a new treatment of the electrostatic correlations for the non-bonded ions and chain connectivity that are approximated by employing a first-order Taylor expansion, with the reference fluid density determined using the technique from Gillespie et al. [D. Gillespie et al., J. Phys.: Condens. Matter, 2002, 14, 12129]. We show that the first-order Taylor expansion for the non-bonded electrostatic correlations yields numerically comparable results to the more involved second-order expansion. Furthermore, we find that the existing treatment of the chain connectivity correlation predicts a spurious layer-by-layer phase at moderately large Bjerrum lengths, which is avoided in our new treatment. These simplifications and improvements should significantly facilitate the implementation and reduce the computational cost.", "date": "2018-07-28", "date_type": "published", "publication": "Soft Matter", "volume": "14", "number": "28", "publisher": "Royal Society of Chemistry", "pagerange": "5878-5887", "id_number": "CaltechAUTHORS:20180628-112107625", "issn": "1744-683X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180628-112107625", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" } ] }, "doi": "10.1039/c8sm00595h", "resource_type": "article", "pub_year": "2018", "author_list": "Jiang, Jian; Ginzburg, Valeriy V.; et el." }, { "id": "https://authors.library.caltech.edu/records/9bhpv-g5s39", "eprint_id": 86845, "eprint_status": "archive", "datestamp": "2023-08-19 09:50:22", "lastmod": "2023-10-18 20:38:19", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Webb-M-A", "name": { "family": "Webb", "given": "Michael A." }, "orcid": "0000-0002-7420-4474" }, { "id": "Yamamoto-Umi", "name": { "family": "Yamamoto", "given": "Umi" } }, { "id": "Savoie-B-M", "name": { "family": "Savoie", "given": "Brett M." }, "orcid": "0000-0002-7039-4039" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Miller-T-F-III", "name": { "family": "Miller", "given": "Thomas F., III" }, "orcid": "0000-0002-1882-5380" } ] }, "title": "Globally Suppressed Dynamics in Ion-Doped Polymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: March 30, 2018; Accepted: June 4, 2018; Published: June 6, 2018. \n\nThis research was supported by the National Science Foundation under DMREF Award Number NSF-CHE-1335486. M.A.W. also acknowledges support from the Resnick Sustainability Institute. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - mz8b00237_si_001.pdf
", "abstract": "We investigate how ion\u2013polymer complexation suppresses molecular motion in conventional polymer electrolytes using molecular dynamics (MD) simulations of lithium hexafluorophosphate in poly(ethylene oxide) and a modified Rouse model. The employed model utilizes an inhomogeneous friction distribution to describe ion\u2013polymer interactions and provides an effective way to examine how ion\u2013polymer interactions affect polymer motion. By characterizing the subdiffusive Li^+ transport and polymer relaxation times at several salt concentrations, we observe that increases in local friction due to ion-polymer complexation are significantly smaller than previously assumed. We find that a Rouse-based model that only considers local increases in friction cannot simultaneously capture the magnitude of increased polymer relaxation times and the apparent power-law exponent for Li^+ subdiffusion observed in MD simulations. This incompatibility is reconciled by augmenting the modified Rouse model with a term that increases the global friction with the square of the salt concentration; this significantly improves the agreement between the model and MD, indicating the importance of ion\u2013ion interactions and distributions on ion/polymer mobility.", "date": "2018-06-19", "date_type": "published", "publication": "ACS Macro Letters", "volume": "7", "number": "6", "publisher": "American Chemical Society", "pagerange": "734-738", "id_number": "CaltechAUTHORS:20180606-124846827", "issn": "2161-1653", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180606-124846827", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1335486" }, { "agency": "Resnick Sustainability Institute" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC05-00OR22725" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acsmacrolett.8b00237", "primary_object": { "basename": "mz8b00237_si_001.pdf", "url": "https://authors.library.caltech.edu/records/9bhpv-g5s39/files/mz8b00237_si_001.pdf" }, "resource_type": "article", "pub_year": "2018", "author_list": "Webb, Michael A.; Yamamoto, Umi; et el." }, { "id": "https://authors.library.caltech.edu/records/27x1y-1ha05", "eprint_id": 84896, "eprint_status": "archive", "datestamp": "2023-08-19 08:19:41", "lastmod": "2023-10-18 16:57:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shen-Kevin", "name": { "family": "Shen", "given": "Kevin" }, "orcid": "0000-0001-9715-7474" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Polyelectrolyte Chain Structure and Solution Phase Behavior", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2018 American Chemical Society. \n\nReceived: December 19, 2017; Revised: January 29, 2018; Publication Date (Web): February 20, 2018. \n\nThe authors thank Pengfei Zhang for helpful discussions. K.S. also gratefully acknowledges support by the NSF-GRFP Grant DGE-1745301 and the Jacobs Institute for Molecular Engineering for Medicine. \n\nThe authors declare no competing financial interest.", "abstract": "Using a recently developed renormalized Gaussian fluctuation (RGF) field theory that self-consistently accounts for the concentration-dependent coupling between chain structure and electrostatic correlations, we study the phase behavior of polyelectrolyte solutions, with a focus on the effects of added salts and chain structure. For solutions of a single polyelectrolyte species plus salt, the RGF theory predicts the existence of a loop in the phase boundary at Bjerrum lengths (inverse temperature) below (above) the critical value of the salt-free system. This loop behavior can occur at electrostatic interaction strengths lb/b at which the loop no longer exists for the TPT-1 theory, and at fixed lb/b the loop can persist for infinitely long chains, in contrast to theories using a fixed-Gaussian structure (fg-RPA). For systems of oppositely charged (but otherwise symmetric) chains, we again find that the fg-RPA greatly overpredicts the driving force for phase separation, especially at higher charge fractions (but still below the critical Manning charge density). In general, stiff chains have a narrower two-phase region than intrinsically flexible chains, although intrinsically flexible chains can still experience a local stiffening which persists in semidilute solution; for higher charge fractions the local stiffening of flexible chains is crucial for reproducing qualitatively correct thermodynamics and phase diagrams. For fully charged flexible chains, we find that phase diagrams are quite similar to those for semiflexible rods and that it is possible to capture the coacervate phase diagrams of the full self-consistent calculations using a constant, renormalized chain stiffness.", "date": "2018-03-13", "date_type": "published", "publication": "Macromolecules", "volume": "51", "number": "5", "publisher": "American Chemical Society", "pagerange": "1706-1717", "id_number": "CaltechAUTHORS:20180221-073146606", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180221-073146606", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1745301" }, { "agency": "Caltech Jacobs Institute for Molecular Engineering for Medicine" } ] }, "doi": "10.1021/acs.macromol.7b02685", "resource_type": "article", "pub_year": "2018", "author_list": "Shen, Kevin and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/tzgc9-j1b58", "eprint_id": 85445, "eprint_status": "archive", "datestamp": "2023-08-19 08:01:12", "lastmod": "2023-10-18 18:14:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Jiang-Jian", "name": { "family": "Jiang", "given": "Jian" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Improved local lattice Monte Carlo simulation for charged systems", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2018 Published by AIP Publishing. \n\nReceived 24 January 2018; accepted 27 February 2018; published online 16 March 2018. \n\nThe Dow Chemical Company is acknowledged for funding and for permission to publish the results. We thank Pengfei Zhang, Anthony Maggs, Issei Nakamura, and Xiaozheng Duan for helpful discussions.\n\nPublished - 1.5023491.pdf
", "abstract": "Maggs and Rossetto [Phys. Rev. Lett. 88, 196402 (2002)] proposed a local lattice Monte Carlo algorithm for simulating charged systems based on Gauss's law, which scales with the particle number N as O(N). This method includes two degrees of freedom: the configuration of the mobile charged particles and the electric field. In this work, we consider two important issues in the implementation of the method, the acceptance rate of configurational change (particle move) and the ergodicity in the phase space sampled by the electric field. We propose a simple method to improve the acceptance rate of particle moves based on the superposition principle for electric field. Furthermore, we introduce an additional updating step for the field, named \"open-circuit update,\" to ensure that the system is fully ergodic under periodic boundary conditions. We apply this improved local Monte Carlo simulation to an electrolyte solution confined between two low dielectric plates. The results show excellent agreement with previous theoretical work.", "date": "2018-03", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "148", "number": "11", "publisher": "American Institute of Physics", "pagerange": "Art. No. 114105", "id_number": "CaltechAUTHORS:20180327-084056793", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180327-084056793", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" } ] }, "doi": "10.1063/1.5023491", "primary_object": { "basename": "1.5023491.pdf", "url": "https://authors.library.caltech.edu/records/tzgc9-j1b58/files/1.5023491.pdf" }, "resource_type": "article", "pub_year": "2018", "author_list": "Jiang, Jian and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/qg427-kb258", "eprint_id": 83337, "eprint_status": "archive", "datestamp": "2023-08-19 06:50:05", "lastmod": "2023-10-17 23:03:27", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "50th Anniversary Perspective: Polymer Conformation\u2014A Pedagogical Review", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: July 17, 2017; Revised: October 20, 2017; Publication Date (Web): November 16, 2017. \n\nI thank Alexander Grosberg, Timothy Lodge, Michael Rubinstein, Sergey Panyukov, Jack Douglas, Nitash Balsara, and Kevin Shen for helpful discussions and Alexander Grosberg, Masao Doi, Karl Freed, and Jian Qin for detailed comments and suggestions on the manuscript. Special thanks go to Kevin Shen, Umi Yamamoto, and Pengfei Zhang for help with the figures and other technical assistance. \n\nThe author declares no competing financial interest.", "abstract": "The study of the conformation properties of macromolecules is at the heart of polymer science. Essentially all physical properties of polymers are manifestations of the underlying polymer conformations or otherwise significantly impacted by the conformation properties. In this Perspective, we review some of the key concepts that we have learned over nearly eight decades of the subject and outline some open questions. The topics include both familiar subjects in polymer physics textbooks and more recent results or not-so-familiar subjects, such as non-Gaussian chain behavior in polymer melts and topological effects in ring polymers. The emphasis is on understanding the key concepts, with both physical reasoning and mathematical analysis, and on the interconnection between the different results and concepts.", "date": "2017-12-12", "date_type": "published", "publication": "Macromolecules", "volume": "50", "number": "23", "publisher": "American Chemical Society", "pagerange": "9073-9114", "id_number": "CaltechAUTHORS:20171120-102752509", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20171120-102752509", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1021/acs.macromol.7b01518", "resource_type": "article", "pub_year": "2017", "author_list": "Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/mqnvf-ej076", "eprint_id": 81404, "eprint_status": "archive", "datestamp": "2023-08-19 05:08:31", "lastmod": "2023-10-17 19:49:45", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Omar-A-K", "name": { "family": "Omar", "given": "Ahmad K." }, "orcid": "0000-0002-6404-7612" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Shear-Induced Heterogeneity in Associating Polymer Gels: Role of Network Structure and Dilatancy", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Physical Society. \n\nReceived 8 July 2016; revised manuscript received 23 April 2017; published 12 September 2017. \n\nWe thank John Brady and Marco Heinen for fruitful discussions. A.\u2009K.\u2009O. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469 and an HHMI Gilliam Fellowship.\n\nPublished - PhysRevLett.119.117801.pdf
Supplemental Material - SM.pdf
", "abstract": "We study associating polymer gels under steady shear using Brownian dynamics simulation to explore the interplay between the network structure, dynamics, and rheology. For a wide range of flow rates, we observe the formation of shear bands with a pronounced difference in shear rate, concentration, and structure. A striking increase in the polymer pressure in the gradient direction with shear, along with the inherently large compressibility of the gels, is shown to be a crucial factor in destabilizing homogeneous flow through shear-gradient concentration coupling. We find that shear has only a modest influence on the degree of association, but induces marked spatial heterogeneity in the network connectivity. We attribute the increase in the polymer pressure (and polymer mobility) to this structural reorganization.", "date": "2017-09-15", "date_type": "published", "publication": "Physical Review Letters", "volume": "119", "number": "11", "publisher": "American Physical Society", "pagerange": "Art. No. 117801", "id_number": "CaltechAUTHORS:20170913-100922884", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170913-100922884", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1144469" }, { "agency": "Howard Hughes Medical Institute (HHMI)" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1103/PhysRevLett.119.117801", "primary_object": { "basename": "PhysRevLett.119.117801.pdf", "url": "https://authors.library.caltech.edu/records/mqnvf-ej076/files/PhysRevLett.119.117801.pdf" }, "related_objects": [ { "basename": "SM.pdf", "url": "https://authors.library.caltech.edu/records/mqnvf-ej076/files/SM.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Omar, Ahmad K. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/p67hb-2e153", "eprint_id": 81234, "eprint_status": "archive", "datestamp": "2023-08-21 21:37:28", "lastmod": "2023-10-17 19:41:02", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lin-Panpan", "name": { "family": "Lin", "given": "Panpan" } }, { "id": "Liu-Jianning", "name": { "family": "Liu", "given": "Jianning" } }, { "id": "Zhao-Zhichen", "name": { "family": "Zhao", "given": "Zhichen" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Wang-Shi-Qing", "name": { "family": "Wang", "given": "Shi-Qing" } } ] }, "title": "Origin of mechanical stress and rising internal energy during fast uniaxial extension of SBR melts", "ispublished": "pub", "full_text_status": "public", "keywords": "Polymer melts; Thermodynamics; Uniaxial extension; Melt rheology", "note": "\u00a9 2017 Elsevier Ltd. \n\nReceived 2 May 2017, Revised 5 July 2017, Accepted 16 July 2017, Available online 17 July 2017.", "abstract": "We carry out simultaneous mechanical and IR-thermal-imaging based temperature measurements of SBR melts during uniaxial extension in order to delineate the nature of the observed mechanical responses. Using the first law of thermodynamics, we evaluate the enthalpy change h_1 associated with the temperature rise in the extending melt, estimate the heat loss to the surrounding, and conclude that there is an appreciable non-thermal enthalpic buildup h_2 = (w \u2013 h_1 \u2212 q) during either adiabatic or isothermal extension. The monotonic increase of h_2 with the stretching ratio \u03bb until the onset of inhomogeneous extension or melt rupture reveals that fast melt extension is largely elastic even after yielding in presence of partial chain disentanglement. At high rates, the lock-up of chain entanglement produces such a high level of h_2 that is rarely seen in extension of crosslinked rubbers. When melt extension is carried out under isothermal condition, we show that the time-temperature superposition principle (TTS) fails to predict the transient response of a SBR melt at a fixed effective rate involving three temperatures. The failure of the TTS suggests that the terminal chain dynamics show different temperature dependence from the local segmental dynamics that control the transient stress responses.", "date": "2017-08-25", "date_type": "published", "publication": "Polymer", "volume": "124", "publisher": "Elsevier", "pagerange": "68-77", "id_number": "CaltechAUTHORS:20170907-083345533", "issn": "0032-3861", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170907-083345533", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1016/j.polymer.2017.07.041", "resource_type": "article", "pub_year": "2017", "author_list": "Lin, Panpan; Liu, Jianning; et el." }, { "id": "https://authors.library.caltech.edu/records/v64ps-r6k53", "eprint_id": 78130, "eprint_status": "archive", "datestamp": "2023-08-19 04:03:53", "lastmod": "2023-10-25 23:47:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Minglun", "name": { "family": "Li", "given": "Minglun" } }, { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } } ] }, "title": "Accurate Determination of Ion Polarizabilities in Aqueous Solutions", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: May 1, 2017; Revised: June 7, 2017; Published: June 8, 2017. \n\nThis work was supported by the National Natural Science Foundation of China (Grant Nos. 21674113 and 21334007) and the International Partnership Program of CAS (Grant No. 121522KYSB20160015). Y.L. acknowledges the Youth Innovation Promotion Association of CAS (Grant No. 2016204) for financial support. B.Z. acknowledges the A-STAR fellowship for financial support. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - acs_2Ejpcb_2E7b04111.pdf
Supplemental Material - jp7b04111_si_002.pdf
", "abstract": "We present a novel method for obtaining salt polarizabilities in aqueous solutions based on our recent theory for the refractive index of salt solutions, which predicts a linear relationship between the refractive index and the salt concentration at low concentrations, with a slope determined by the intrinsic values of the salt polarizability and the density of the solution. Here we apply this theory to determine the polarizabilities of 32 strong electrolyte salts in aqueous solutions from refractive index and density measurements. Setting Li^+ as the standard ion, we then determine the polarizabilities of seven cations (Na^+, K^+, Rb^+, Cs^+, Ca^(2+), Ba^(2+), and Sr^(2+)) and seven anions (F^\u2013, Cl^\u2013, Br^\u2013, I^\u2013, ClO_4^\u2013, NO_3^\u2013, and SO_4^(2\u2013)), which can be used as important reference data. We investigate the effect of temperature on salt polarizabilities, which decreases slightly with increasing temperature. The ion polarizability is found to be proportional to the cube of bare ionic radius (r_(bare)^3) for univalent ions, but the relationship does not hold for multivalent ions. Contrary to findings of Krishnamurti, we find no significant linear relationship between ion polarizability and the square of the atomic number (N^2) for smaller ions.", "date": "2017-07-06", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "121", "number": "26", "publisher": "American Chemical Society", "pagerange": "6416-6424", "id_number": "CaltechAUTHORS:20170612-155734285", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170612-155734285", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21674113" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21334007" }, { "agency": "Chinese Academy of Sciences", "grant_number": "121522KYSB20160015" }, { "agency": "Chinese Academy of Sciences", "grant_number": "2016204" }, { "agency": "Agency for Science, Technology and Research (A*STAR)" } ] }, "doi": "10.1021/acs.jpcb.7b04111", "primary_object": { "basename": "jp7b04111_si_002.pdf", "url": "https://authors.library.caltech.edu/records/v64ps-r6k53/files/jp7b04111_si_002.pdf" }, "related_objects": [ { "basename": "acs_2Ejpcb_2E7b04111.pdf", "url": "https://authors.library.caltech.edu/records/v64ps-r6k53/files/acs_2Ejpcb_2E7b04111.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Li, Minglun; Zhuang, Bilin; et el." }, { "id": "https://authors.library.caltech.edu/records/kxwjw-tsd28", "eprint_id": 75298, "eprint_status": "archive", "datestamp": "2023-08-19 02:07:30", "lastmod": "2023-10-25 14:55:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Miller-T-F-III", "name": { "family": "Miller", "given": "Thomas F., III" }, "orcid": "0000-0002-1882-5380" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Coates-G-W", "name": { "family": "Coates", "given": "Geoffrey W." }, "orcid": "0000-0002-3400-2552" }, { "id": "Balsara-N-P", "name": { "family": "Balsara", "given": "Nitash P." }, "orcid": "0000-0002-0106-5565" } ] }, "title": "Designing Polymer Electrolytes for Safe and High Capacity Rechargeable Lithium Batteries", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: November 11, 2016; Published: March 21, 2017. \n\nThis research was supported by the DMREF (Designing Materials to Revolutionize and Engineer our Future) Program of the National Science Foundation, Award Numbers NSF-CHE-1335486, NSF-CHE-1333736, and NSF-CHE-1334410. We thank our students, Brett Savoie, Danielle Pesko, Mike Webb, and Qi Zheng, for their valuable input. \n\nThe authors declare no competing financial interest", "abstract": "The development of solid polymer electrolytes for lithium battery applications is a challenge of profound technological significance. We have established a collaboration with the aim of understanding and designing improved polymer electrolytes that combines theoretical modeling, polymer synthesis, and experimental characterization. By studying diverse polymer chemistries, we have discovered that ion-solvation-site connectivity is an important feature of polymer electrolytes that is necessary for high lithium-ion conductance. We are employing this insight into search for improved polymer electrolytes, with promising early-stage results.", "date": "2017-03-21", "date_type": "published", "publication": "Accounts of Chemical Research", "volume": "50", "number": "3", "publisher": "American Chemical Society", "pagerange": "590-593", "id_number": "CaltechAUTHORS:20170322-074051393", "issn": "0001-4842", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170322-074051393", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1335486" }, { "agency": "NSF", "grant_number": "CHE-1333736" }, { "agency": "NSF", "grant_number": "CHE-1334410" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/acs.accounts.6b00568", "resource_type": "article", "pub_year": "2017", "author_list": "Miller, Thomas F., III; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/vxq95-yw516", "eprint_id": 74522, "eprint_status": "archive", "datestamp": "2023-08-19 02:02:41", "lastmod": "2023-10-24 22:43:28", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Rapp-P-B", "name": { "family": "Rapp", "given": "Peter B." }, "orcid": "0000-0002-9586-2126" }, { "id": "Omar-A-K", "name": { "family": "Omar", "given": "Ahmad K." }, "orcid": "0000-0002-6404-7612" }, { "id": "Shen-J-J", "name": { "family": "Shen", "given": "Jeff J." } }, { "id": "Buck-M-E", "name": { "family": "Buck", "given": "Maren E." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Tirrell-D-A", "name": { "family": "Tirrell", "given": "David A." }, "orcid": "0000-0003-3175-4596" } ] }, "title": "Analysis and control of chain mobility in protein hydrogels", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 American Chemical Society. \n\nReceived: December 30, 2016; Published: February 22, 2017. \n\nWe thank Steven Olsen and the Division of Chemistry and Chemical Engineering Instrument Shop for machining sample holders for the FRAP experiments. We also thank David Koos, Andres Collazo and the Biological Imaging Facility of the Caltech Beckman Institute for training and assistance in operating the confocal microscope. We thank John Bagert, Lawrence Dooling, and Cole DeForest for helpful discussions during the preparation of the manuscript. \n\nThis work was supported by grant number DMR-1506483 from the Biomaterials Program of the U. S. National Science Foundation. A.K.O. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469 and an HHMI Gilliam Fellowship. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - jacs_2E6b13146.pdf
Supplemental Material - ja6b13146_si_001.pdf
", "abstract": "Coiled-coil domains can direct the assembly of protein block copolymers into physically crosslinked, viscoelastic hydrogels. Here we describe the use of fluorescence recovery after photobleaching (FRAP) to probe chain mobility in reversible hydrogels assembled from engineered proteins bearing terminal coiled-coil domains. We show that chain mobility can be related to the underlying dynamics of the coiled-coil domains by application of a 3-state \"hopping\" model of chain migration. We further show that genetic programming allows the effective mobility of network chains to be varied 500-fold through modest changes in protein sequence. Destabilization of the coiled-coil domains by site-directed mutagenesis increases the effective diffusivity of probe chains. Conversely, probe mobility is reduced by expanding the hydrophobic surface area of the coiled-coil domains through introduction of the bulky leucine surrogate homoisoleucine. Predictions from the 3-state model imply asymmetric sequential binding of the terminal domains. Brownian Dynamics simulations suggest that binding asymmetry is a general feature of reversible gels, arising from a loss in entropy as chains transition to a conformationally restricted bridged state.", "date": "2017-03-15", "date_type": "published", "publication": "Journal of the American Chemical Society", "volume": "139", "number": "10", "publisher": "American Chemical Society", "pagerange": "3796-3804", "id_number": "CaltechAUTHORS:20170224-091637468", "issn": "0002-7863", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170224-091637468", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-1506483" }, { "agency": "NSF Graduate Research Fellowship", "grant_number": "DGE-1144469" }, { "agency": "Howard Hughes Medical Institute (HHMI)" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/jacs.6b13146", "primary_object": { "basename": "ja6b13146_si_001.pdf", "url": "https://authors.library.caltech.edu/records/vxq95-yw516/files/ja6b13146_si_001.pdf" }, "related_objects": [ { "basename": "jacs_2E6b13146.pdf", "url": "https://authors.library.caltech.edu/records/vxq95-yw516/files/jacs_2E6b13146.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Rapp, Peter B.; Omar, Ahmad K.; et el." }, { "id": "https://authors.library.caltech.edu/records/9q7zx-tey21", "eprint_id": 74525, "eprint_status": "archive", "datestamp": "2023-08-19 01:41:10", "lastmod": "2023-10-24 22:43:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Shen-Kevin", "name": { "family": "Shen", "given": "Kevin" }, "orcid": "0000-0001-9715-7474" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Electrostatic correlations and the polyelectrolyte self energy", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2017 AIP Publishing LLC. \n\n(Received 11 November 2016; accepted 26 January 2017; published online 23 February 2017) \n\nThe authors would like to thank Bilin Zhuang, Rui Wang, Pengfei Zhang, and Marco Heinen, for helpful discussions. Special thanks go to Professor Jian Qin for his insightful comments on our manuscript. K.S. acknowledges support by the NSF-GRFP fellowship.\n\nPublished - 1_2E4975777.pdf
Submitted - 1701.00214.pdf
", "abstract": "We address the effects of chain connectivity on electrostatic fluctuations in polyelectrolyte solutions using a field-theoretic, renormalizedGaussian fluctuation (RGF) theory. As in simple electrolyte solutions [Z.-G. Wang, Phys. Rev. E 81, 021501 (2010)], the RGF provides a unified theory for electrostatic fluctuations, accounting for both dielectric and charge correlation effects in terms of the self-energy. Unlike simple ions, the polyelectrolyte self energy depends intimately on the chain conformation, and our theory naturally provides a self-consistent determination of the response of intramolecular chain structure to polyelectrolyte and salt concentrations. The effects of the chain-conformation on the self-energy and thermodynamics are especially pronounced for flexible polyelectrolytes at low polymer and salt concentrations, where application of the wrong chain structure can lead to a drastic misestimation of the electrostatic correlations. By capturing the expected scaling behavior of chain size from dilute to semi-dilute regimes, our theory provides improved estimates of the self energy at low polymer concentrations and correctly predicts the eventual N-independence of the critical temperature and concentration of salt-free solutions of flexible polyelectrolytes. We show that the self energy can be interpreted in terms of an infinite-dilution energy \u03bc^(el)_(m,0) and a finite concentration correlation correction \u03bc^(corr) which tends to cancel out the former with increasing concentration.", "date": "2017-02-28", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "146", "number": "8", "publisher": "American Institute of Physics", "pagerange": "Art. No. 084901", "id_number": "CaltechAUTHORS:20170224-103032443", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170224-103032443", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1063/1.4975777", "primary_object": { "basename": "1_2E4975777.pdf", "url": "https://authors.library.caltech.edu/records/9q7zx-tey21/files/1_2E4975777.pdf" }, "related_objects": [ { "basename": "1701.00214.pdf", "url": "https://authors.library.caltech.edu/records/9q7zx-tey21/files/1701.00214.pdf" } ], "resource_type": "article", "pub_year": "2017", "author_list": "Shen, Kevin and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/tyxcv-7cx36", "eprint_id": 74659, "eprint_status": "archive", "datestamp": "2023-08-22 19:45:01", "lastmod": "2023-10-24 22:50:03", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Alsaifi-N-M", "name": { "family": "Alsaifi", "given": "Nayef M." }, "orcid": "0000-0003-3232-6411" }, { "id": "Al-Aslani-I", "name": { "family": "Al Aslani", "given": "Isa" } }, { "id": "Binous-H", "name": { "family": "Binous", "given": "Housam" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "A priori determination of the region of the three physical volume root loci in the Perturbed-Chain SAFT EOS", "ispublished": "pub", "full_text_status": "public", "keywords": "Equation of state; PC-SAFT; Bifurcation diagrams; Volume roots", "note": "\u00a9 2016 Elsevier B.V. \n\nReceived 28 September 2016, Revised 12 November 2016, Accepted 24 November 2016, Available online 26 November 2016.", "abstract": "In this work, the physical region exhibiting the common three volume roots is located a priori for the Perturbed-Chain Statistical Association Fluid Theory (PC-SAFT) equation of state without the need to determine the other non-physical volume roots. The loci of all multiple volume roots are first determined and investigated for the PC-SAFT equation of state over a broad range of temperatures and pressures using bifurcation diagrams. The study then illustrates how the number of multiple volume roots varies with temperature and pressure. The influence of each SAFT term is studied for several kinds of fluids ranging from spherical molecules to polymers. The technique presented in this study provides a simple method to identify artificial two-phase separation regions. Our study demonstrates that the problem of multiple volume roots found in non-cubic equations of state can be easily managed once the variation of volume loci with temperature and pressure are analyzed and understood using bifurcation diagrams.", "date": "2017-02-25", "date_type": "published", "publication": "Fluid Phase Equilibria", "volume": "434", "publisher": "Elsevier", "pagerange": "152-166", "id_number": "CaltechAUTHORS:20170301-153738586", "issn": "0378-3812", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170301-153738586", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1016/j.fluid.2016.11.023", "resource_type": "article", "pub_year": "2017", "author_list": "Alsaifi, Nayef M.; Al Aslani, Isa; et el." }, { "id": "https://authors.library.caltech.edu/records/txdth-7qx34", "eprint_id": 72763, "eprint_status": "archive", "datestamp": "2023-08-19 00:39:14", "lastmod": "2023-10-23 22:55:19", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Pengfei", "name": { "family": "Zhang", "given": "Pengfei" } }, { "id": "Alsaifi-N-M", "name": { "family": "Alsaifi", "given": "Nayef M." }, "orcid": "0000-0003-3232-6411" }, { "id": "Wu-Jianzhong", "name": { "family": "Wu", "given": "Jianzhong" }, "orcid": "0000-0002-4582-5941" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Salting-Out and Salting-In of Polyelectrolyte Solutions: A Liquid-State Theory Study", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: October 5, 2016; Revised: November 23, 2016; Publication Date (Web): December 12, 2016. \n\nThis work was conducted jointly by King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia and California Institute of Technology (Caltech) under a collaborative research program in catalysis. The authors gratefully acknowledge the support provided by KFUPM and Caltech. J.W. acknowledges partial financial support from the US National Science Foundation (Grant No. NSF-CBET-820 0852353). \n\nThe authors declare no competing financial interest.", "abstract": "We study the phase behavior of polyelectrolyte (PE) solutions with salt using a simple liquid-state (LS) theory. This LS theory accounts for hard-core excluded volume repulsion by the Boublik\u2013Mansoori\u2013Carnahan\u2013Starling\u2013Leland equation of state, electrostatic correlation by the mean-spherical approximation, and chain connectivity by the first-order thermodynamic perturbation theory. We predict a closed-loop binodal curve in the PE concentration-salt concentration phase diagram when the Bjerrum length is smaller than the critical Bjerrum length in salt-free PE solution. The phase-separated region shrinks with decreasing Bjerrum length, and disappears below a critical Bjerrum length. These results are qualitatively consistent with experiments, but cannot be captured by the Voorn\u2013Overbeek theory. On the basis of the closed-loop binodal curve and the lever rule, we predict three scenarios of salting-out and salting-in phenomena with addition of monovalent salt into an initially salt-free PE solution. The Galvani potential\u2014the electric potential difference between the coexisting phases\u2014is found to depend nonmonotonically on the overall salt concentration in some PE concentration range, which is related to the partition of the co-ions in the coexisting phases. Free energy analysis suggests that phase separation is driven by a gain in the electrostatic energy, at the expense of a large translational entropy penalty, due to significant counterion accumulation in the PE-rich phase.", "date": "2016-12-27", "date_type": "published", "publication": "Macromolecules", "volume": "49", "number": "24", "publisher": "American Chemical Society", "pagerange": "9720-9730", "id_number": "CaltechAUTHORS:20161213-100941959", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161213-100941959", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "King Fahd University of Petroleum and Minerals (KFUPM)" }, { "agency": "Caltech" }, { "agency": "NSF", "grant_number": "CBET-820 0852353" } ] }, "doi": "10.1021/acs.macromol.6b02160", "resource_type": "article", "pub_year": "2016", "author_list": "Zhang, Pengfei; Alsaifi, Nayef M.; et el." }, { "id": "https://authors.library.caltech.edu/records/a3yd8-n1h64", "eprint_id": 67283, "eprint_status": "archive", "datestamp": "2023-08-20 12:47:41", "lastmod": "2023-10-18 21:03:16", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Molecularly-Based Theory for Electron Transfer Reorganization Energy in Solvent Mixtures", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: March 31, 2016. Revised: May 17, 2016. Publication Date (Web): May 17, 2016. \n\nSpecial Issue: William M. Gelbart Festschrift. \n\nWe thank Professors Rudolph Marcus, Thomas Miller III, David Tirrell, and Mr. Kevin Shen for helpful discussions. B.Z. gratefully acknowledges the support by an A-STAR fellowship. Acknowledgment is also made to the donors of the American Chemical Society Petroleum Research Fund for partial support of this research. \n\nThe authors declare no competing financial interest.\n\nAccepted Version - acs_2Ejpcb_2E6b03295.pdf
Supplemental Material - jp6b03295_si_001.pdf
", "abstract": "Using statistical-field techniques, we develop a molecular-based dipolar self-consistent-field theory (DSCFT) for charge solvation in liquid mixtures under equilibrium and nonequilibrium conditions, and apply it to compute the solvent reorganization energy of electron-transfer reactions. In addition to the nonequilibrium orientational polarization, the reorganization energy in liquid mixtures is also determined by the out-of-equilibrium solvent composition around the reacting species due to preferential solvation. Using molecular parameters that are readily available, the DSCFT naturally accounts for the dielectric saturation effect and the spatially varying solvent composition in the vicinity of the reacting species. We identify three general categories of binary solvent mixtures, classified by the relative optical and static dielectric permittivities of the solvent components. Each category of mixture is shown to produce a characteristic local solvent composition profile in the vicinity of the reacting species, which gives rise to the distinctive composition dependence of the reorganization energy that cannot be predicted using the dielectric permittivities of the homogeneous solvent mixtures.", "date": "2016-07-07", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "120", "number": "26", "publisher": "American Chemical Society", "pagerange": "6373-6382", "id_number": "CaltechAUTHORS:20160524-080318394", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160524-080318394", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Agency for Science, Technology and Research (A*STAR)" }, { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1021/acs.jpcb.6b03295", "primary_object": { "basename": "acs_2Ejpcb_2E6b03295.pdf", "url": "https://authors.library.caltech.edu/records/a3yd8-n1h64/files/acs_2Ejpcb_2E6b03295.pdf" }, "related_objects": [ { "basename": "jp6b03295_si_001.pdf", "url": "https://authors.library.caltech.edu/records/a3yd8-n1h64/files/jp6b03295_si_001.pdf" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Zhuang, Bilin and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/8287q-9e854", "eprint_id": 67588, "eprint_status": "archive", "datestamp": "2023-08-22 17:52:24", "lastmod": "2023-10-18 21:18:46", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Bing", "name": { "family": "Li", "given": "Bing" } }, { "id": "Sun-Zhaoyang", "name": { "family": "Sun", "given": "Zhaoyang" } }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "The scaling behavior of the second virial coefficient of linear and ring polymer", "ispublished": "pub", "full_text_status": "restricted", "keywords": "second virial coefficient; topological constraints; 3-body interactions; theta temperature; scaling behavior", "note": "\u00a9 2015 Science China Press and Springer-Verlag. \n\nReceived August 29, 2015; accepted September 25, 2015; published online December 30, 2015. \n\nThis work was supported by the National Basic Research Program of China (2012CB821500) and the National Natural Science Foundation of China (21222407, 21474111). \n\nThe authors declare that they have no conflict of interest", "abstract": "The scaling behavior of the second virial coefficient of ring polymers at the theta temperature of the corresponding linear polymer (\u03b8_L) is investigated by off-lattice Monte Carlo simulations. The effects of the solvents are modeled by pairwise interaction between polymer monomers in this approach. Using the umbrella sampling, we calculate the effective potential U(r) between two ring polymers as well as the second virial coefficient A_2 of ring polymers at \u03b8_L, which results from a combination of 3-body interactions and topological constraints. The trend in the strength of the effective potential with respect to chain length shows a non-monotonic behavior, differently from that caused only by topological constraints. Our simulation suggests that there are three regimes about the scaling behavior of A_2 of ring polymers at \u03b8_L: 3-body interactions dominating regime, the crossover regime, and the topological constraints dominating regime.", "date": "2016-05", "date_type": "published", "publication": "Science China Chemistry", "volume": "59", "number": "5", "publisher": "Springer", "pagerange": "619-623", "id_number": "CaltechAUTHORS:20160602-150436719", "issn": "1674-7291", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160602-150436719", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Basic Research Program of China", "grant_number": "2012CB821500" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21222407" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21474111" } ] }, "doi": "10.1007/s11426-015-5531-6", "resource_type": "article", "pub_year": "2016", "author_list": "Li, Bing; Sun, Zhaoyang; et el." }, { "id": "https://authors.library.caltech.edu/records/t6441-hyz73", "eprint_id": 59440, "eprint_status": "archive", "datestamp": "2023-08-20 11:14:00", "lastmod": "2023-10-23 20:36:01", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Inhomogeneous screening near a dielectric interface", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2016 AIP Publishing LLC. \n\nReceived 18 November 2015; accepted 18 March 2016; published online 5 April 2016. \n\nAcknowledgment is made to the donors of the American Chemical Society Petroleum Research Fund for partial support of this research.\n\nPublished - 1.4945011.pdf
Submitted - 1505.07340v1.pdf
", "abstract": "Screening is one of the most important concepts in the study of charged systems. Near a dielectricinterface, the ion distribution in a salt solution can be highly nonuniform. Here, we develop a theory that self-consistently treats the inhomogeneous screening effects. At higher concentrations when the bulk Debye screening length is comparable to the Bjerrum length, the double layerstructure and interfacial properties are significantly affected by the inhomogeneous screening. In particular, the depletion zone is considerably wider than that predicted by the bulk screening approximation or the WKB approximation. The characteristic length of the depletion layer in this regime scales with the Bjerrum length, resulting in a linear increase of the negative adsorption of ions with concentration, in agreement with experiments. For asymmetric salts, inhomogeneous screening leads to enhanced charge separation and surface potential.", "date": "2016-04-07", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "144", "number": "13", "publisher": "American Institute of Physics", "pagerange": "Art. No. 134902", "id_number": "CaltechAUTHORS:20150812-091441877", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150812-091441877", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1063/1.4945011", "primary_object": { "basename": "1.4945011.pdf", "url": "https://authors.library.caltech.edu/records/t6441-hyz73/files/1.4945011.pdf" }, "related_objects": [ { "basename": "1505.07340v1.pdf", "url": "https://authors.library.caltech.edu/records/t6441-hyz73/files/1505.07340v1.pdf" } ], "resource_type": "article", "pub_year": "2016", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/40bw7-pct32", "eprint_id": 64407, "eprint_status": "archive", "datestamp": "2023-08-20 09:54:37", "lastmod": "2023-10-17 21:17:14", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ren-Chun-Lai", "name": { "family": "Ren", "given": "Chun-Lai" } }, { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of Ion-Induced Cross-Linking on the Phase Behavior in Salt-Doped Polymer Blends", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2016 American Chemical Society. \n\nReceived: October 8, 2015. Revised: December 16, 2015. Published: December 28, 2015. \n\nThis work is supported in part by the National Natural Science Foundation of China under Grant Nos. 21274062 and 21474112. \n\nThe authors declare no competing financial interest.", "abstract": "Taking PEO/PS polymer blends doped with lithium salt as example, we study the effects of cross-linking of the EO segments by the Li^+ ions on the phase behavior. Combining the Flory\u2013Huggins theory with a statistical model accounting for the combinatorics in forming the cross-links and accounting for the charge neutrality due to the presence of anions, we find an entropic driving force that favors phase separation when the number of EO segments coordinating an Li^+ ion exceeds 2. As a result of the asymmetric interaction between the ions and the two polymers, the phase diagram in the polymer composition becomes asymmetric upon addition of the lithium salts. In addition, we examine the effects of preferential solvation energy of the ions which has been shown previously to lead to an increase in the effective \u03c7 parameter between the two polymers. We find that the magnitudes of these two driving forces are comparable, but their effects are nonadditive.", "date": "2016-01-12", "date_type": "published", "publication": "Macromolecules", "volume": "49", "number": "1", "publisher": "American Chemical Society", "pagerange": "425-431", "id_number": "CaltechAUTHORS:20160211-082427816", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160211-082427816", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21274062" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21474112" } ] }, "doi": "10.1021/acs.macromol.5b02229", "resource_type": "article", "pub_year": "2016", "author_list": "Ren, Chun-Lai; Nakamura, Issei; et el." }, { "id": "https://authors.library.caltech.edu/records/b4h2q-6ht49", "eprint_id": 63105, "eprint_status": "archive", "datestamp": "2023-08-20 09:29:21", "lastmod": "2023-10-25 23:31:10", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "A molecularly based theory for electron transfer reorganization energy", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 AIP Publishing LLC. \n\nReceived 27 May 2015; accepted 16 November 2015; published online 8 December 2015. \n\nWe gratefully acknowledge helpful discussions with Professor Rudolph A. Marcus and Professor Thomas F. Miller III. B.Z. acknowledges the A-STAR fellowship for the financial support.\n\nPublished - 1.4936586.pdf
", "abstract": "Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transferreactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule's permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectrictheory.", "date": "2015-12-14", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "143", "number": "22", "publisher": "American Institute of Physics", "pagerange": "Art. No. 224502", "id_number": "CaltechAUTHORS:20151221-130932462", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151221-130932462", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Agency for Science, Technology and Research (A*STAR)" } ] }, "doi": "10.1063/1.4936586", "primary_object": { "basename": "1.4936586.pdf", "url": "https://authors.library.caltech.edu/records/b4h2q-6ht49/files/1.4936586.pdf" }, "resource_type": "article", "pub_year": "2015", "author_list": "Zhuang, Bilin and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/wetk6-zyh66", "eprint_id": 63388, "eprint_status": "archive", "datestamp": "2023-08-20 09:27:30", "lastmod": "2023-10-25 23:47:02", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Bing", "name": { "family": "Li", "given": "Bing" } }, { "id": "Sun-Zhao-Yan", "name": { "family": "Sun", "given": "Zhao-Yan" } }, { "id": "An-Lijia", "name": { "family": "An", "given": "Li-Jia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Influence of Topology on the Free Energy and Metric Properties of an Ideal Ring Polymer Confined in a Slit", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. \n\nReceived: September 14, 2015. Revised: November 11, 2015. Published: November 18, 2015. Published in print 8 December 2015. \n\nThis work is subsidized by the National Basic Research Program of China (973 Program, 2012CB821500), and supported by the National Natural Science Foundation of China (21222407, 21474111). Z.-Y.S thanks Prof. Da-Dong Yan for fruitful discussions and helpful comments. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma5b02026_si_001.pdf
", "abstract": "Using off-lattice Monte Carlo simulation, we investigate the effects of topological constraints on the free energy and metric properties of an unknotted ring polymer without exclude volume interactions confined in a slit with width d, as well as the effect of confinement on the probability of forming an unknot in a freely jointed ring. Because of the topological constraints, the polymer size of an unknotted ring is shown to behave differently from that of a freely jointed ring: the in-plane radius of gyration R_(g\u2225) increases with increasing confinement. However, the free energy of an unknotted ring follows the same scaling law as a freely jointed ring for strong confinement. This abnormal phenomenon is explained on the basis of the fact that the length of subchains inside the confinement blobs is smaller than the topological blob size, i.e., the characteristic length below which topological constraints become unimportant. As in the bulk, the probability of forming an unknot decreases exponentially with the chain length, but the decay length decreases with decreasing confinement length. We propose an efficient method for calculating the probability of forming unknot from a freely jointed ring in confinement.", "date": "2015-12-08", "date_type": "published", "publication": "Macromolecules", "volume": "48", "number": "23", "publisher": "American Chemical Society", "pagerange": "8675-8680", "id_number": "CaltechAUTHORS:20160105-135117569", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160105-135117569", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Basic Research Program of China", "grant_number": "2012CB821500" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "21222407" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "21474111" } ] }, "doi": "10.1021/acs.macromol.5b02026", "primary_object": { "basename": "ma5b02026_si_001.pdf", "url": "https://authors.library.caltech.edu/records/wetk6-zyh66/files/ma5b02026_si_001.pdf" }, "resource_type": "article", "pub_year": "2015", "author_list": "Li, Bing; Sun, Zhao-Yan; et el." }, { "id": "https://authors.library.caltech.edu/records/7wtcv-z1q73", "eprint_id": 60596, "eprint_status": "archive", "datestamp": "2023-08-20 08:39:03", "lastmod": "2023-10-24 16:42:38", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Webb-M-A", "name": { "family": "Webb", "given": "Michael A." }, "orcid": "0000-0002-7420-4474" }, { "id": "Savoie-B-M", "name": { "family": "Savoie", "given": "Brett M." }, "orcid": "0000-0002-7039-4039" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Miller-T-F-III", "name": { "family": "Miller", "given": "Thomas F., III" }, "orcid": "0000-0002-1882-5380" } ] }, "title": "Chemically Specific Dynamic Bond Percolation Model for Ion Transport in Polymer Electrolytes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. \n\nReceived: June 30, 2015; Revised: August 12, 2015; Published online: September 25, 2015. \n\nThis research was supported by the Resnick Sustainability Institute and the National Science Foundation under DMREF Award NSF-CHE-1335486. We acknowledge computing resources from the National Energy Research Scientific Computing Center (DE-AC02-05CH11231). Additionally, we thank Umi Yamamoto, Geoffrey Coates, and Nitash Balsara for helpful discussions. \n\nThe authors declare no competing financial interest.\n\nSupplemental Material - ma5b01437_si_001.pdf
Supplemental Material - ma5b01437_si_002.pdf
Supplemental Material - ma5b01437_si_003.mpg
Supplemental Material - ma5b01437_si_004.mpg
", "abstract": "We introduce a coarse-grained approach for characterizing the long-timescale dynamics of ion diffusion in general polymer electrolytes using input from short molecular dynamics trajectories. The approach includes aspects of the dynamic bond percolation model [ J. Chem. Phys. 1983, 79, 3133\u22123142] by treating ion diffusion in terms of hopping transitions on a fluctuating lattice. We extend this well-known approach by using short (i.e., 10 ns) molecular dynamics (MD) trajectories to predict the distribution of ion solvation sites that comprise the lattice and to predict the rate of hopping among the lattice sites. This yields a chemically specific dynamic bond percolation (CS-DBP) model that enables the description of long-timescale ion diffusion in polymer electrolytes at a computational cost that makes feasible the screening of candidate materials. We employ the new model to characterize lithium-ion diffusion properties in six polyethers that differ by oxygen content and backbone stiffness: poly(trimethylene oxide), poly(ethylene oxide-alt-trimethylene oxide), poly(ethylene oxide), poly(propylene oxide), poly(ethylene oxide-alt-methylene oxide), and poly(methylene oxide). Good agreement is observed between the predictions of the CS-DBP model and long-timescale atomistic MD simulations, thus providing validation of the model. Among the most striking results from this analysis is the unexpectedly good lithium-ion diffusivity of poly(trimethylene oxide-alt-ethylene oxide) by comparison to poly(ethylene oxide), which is widely used. Additionally, the model straightforwardly reveals a range of polymer features that lead to low lithium-ion diffusivity, including the competing effects of the density of solvation sites and polymer stiffness. These results illustrate the potential of the CS-DBP model to screen polymer electrolytes on the basis of ion diffusivity and to identify important design criteria.", "date": "2015-10-13", "date_type": "published", "publication": "Macromolecules", "volume": "48", "number": "19", "publisher": "American Chemical Society", "pagerange": "7346-7358", "id_number": "CaltechAUTHORS:20150929-202516731", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150929-202516731", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Resnick Sustainability Institute" }, { "agency": "NSF", "grant_number": "CHE-1335486" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acs.macromol.5b01437", "primary_object": { "basename": "ma5b01437_si_001.pdf", "url": "https://authors.library.caltech.edu/records/7wtcv-z1q73/files/ma5b01437_si_001.pdf" }, "related_objects": [ { "basename": "ma5b01437_si_002.pdf", "url": "https://authors.library.caltech.edu/records/7wtcv-z1q73/files/ma5b01437_si_002.pdf" }, { "basename": "ma5b01437_si_003.mpg", "url": "https://authors.library.caltech.edu/records/7wtcv-z1q73/files/ma5b01437_si_003.mpg" }, { "basename": "ma5b01437_si_004.mpg", "url": "https://authors.library.caltech.edu/records/7wtcv-z1q73/files/ma5b01437_si_004.mpg" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Webb, Michael A.; Savoie, Brett M.; et el." }, { "id": "https://authors.library.caltech.edu/records/g1v19-g2x32", "eprint_id": 60344, "eprint_status": "archive", "datestamp": "2023-08-20 07:53:00", "lastmod": "2023-10-24 16:27:24", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Xiaofei", "name": { "family": "Xu", "given": "Xiaofei" } }, { "id": "Cristancho-D-E", "name": { "family": "Cristancho", "given": "Diego E." } }, { "id": "Costeux-S", "name": { "family": "Costeux", "given": "St\u00e9phane" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Density-Functional Theory for Mixtures of AB Random Copolymer and CO_2", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2015 American Chemical Society.\n\nReceived: May 25, 2015; Revised: July 15, 2015; Published: August 3, 2015. \n\nThe Dow Chemical Company is acknowledged for funding and for permission to publish the results. X.X. expresses thanks for the support of the National Natural Science Foundation of China (No. 21404078). \n\nThe authors declare no competing financial interests.", "abstract": "We propose a density-functional theory (DFT) to describe inhomogeneous mixtures of AB random copolymer and carbon dioxide (CO_2). The statistical sequence of monomer in the polymer chain backbone is modeled by a transition matrix in a Markov-step growth process. The parameters of the theory are determined by fitting the bulk experimental data. We apply the DFT to the interfacial properties of binary mixtures of CO_2 with poly(methyl methacrylate co ethyl methacrylate) (P(MMA-co-EMA)), poly(methyl methacrylate co ethyl acrylate) (P(MMA-co-EA) and poly(styrene co ethyl acrylate) (P(S-co-EA)). The dependence of CO_2 solubility and interfacial tension on the copolymer composition and pressure is examined. We find that higher fractions of EA or EMA result in higher solubility of CO_2 at a given pressure, but also results in higher interfacial tension at a fixed CO_2 content in the polymer-rich phase. Using the classical nucleation theory as a rough estimate, we examine the effect of the copolymer composition on the free energy barrier of bubble nucleation in random copolymer\u2013CO_2 mixtures.", "date": "2015-08-25", "date_type": "published", "publication": "Macromolecules", "volume": "48", "number": "16", "publisher": "American Chemical Society", "pagerange": "6035-6046", "id_number": "CaltechAUTHORS:20150918-144002667", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150918-144002667", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21404078" } ] }, "doi": "10.1021/acs.macromol.5b01122", "resource_type": "article", "pub_year": "2015", "author_list": "Xu, Xiaofei; Cristancho, Diego E.; et el." }, { "id": "https://authors.library.caltech.edu/records/xmxmy-cdg82", "eprint_id": 60182, "eprint_status": "archive", "datestamp": "2023-08-20 07:49:41", "lastmod": "2023-10-24 14:57:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "An-Ni", "name": { "family": "An", "given": "Ni" } }, { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Li-Minglun", "name": { "family": "Li", "given": "Minglun" } }, { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Combined Theoretical and Experimental Study of Refractive Indices of Water\u2013Acetonitrile\u2013Salt Systems", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: June 8, 2015; Revised: July 14, 2015; Published: July 23, 2015.\n\nThis work is supported, in part, by the National Natural Science Foundation of China (Nos. 21120102037 and 21304097). B.Z. acknowledges the A-STAR fellowship for financial support. We thank the anonymous reviewers, whose comments have helped improve the presentation of our work.\n\nPublished - acs.jpcb.5b05433.pdf
Supplemental Material - jp5b05433_si_001.pdf
", "abstract": "We propose a simple theoretical formula for describing the refractive indices in binary liquid mixtures containing salt ions. Our theory is based on the Clausius\u2013Mossotti equation; it gives the refractive index of the mixture in terms of the refractive indices of the pure liquids and the polarizability of the ionic species, by properly accounting for the volume change upon mixing. The theoretical predictions are tested by extensive experimental measurements of the refractive indices for water\u2013acetonitrile-salt systems for several liquid compositions, different salt species, and a range of salt concentrations. Excellent agreement is obtained in all cases, especially at low salt concentrations, with no fitting parameters. A simplified expression of the refractive index for low salt concentration is also given, which can be the theoretical basis for determination of salt concentration using refractive index measurements.", "date": "2015-08-20", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "119", "number": "33", "publisher": "American Chemical Society", "pagerange": "10701-10709", "id_number": "CaltechAUTHORS:20150911-091014738", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150911-091014738", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21120102037" }, { "agency": "National Natural Science Foundation of China", "grant_number": "21304097" }, { "agency": "Agency for Science, Technology and Research (A*STAR)" } ] }, "doi": "10.1021/acs.jpcb.5b05433", "primary_object": { "basename": "acs.jpcb.5b05433.pdf", "url": "https://authors.library.caltech.edu/records/xmxmy-cdg82/files/acs.jpcb.5b05433.pdf" }, "related_objects": [ { "basename": "jp5b05433_si_001.pdf", "url": "https://authors.library.caltech.edu/records/xmxmy-cdg82/files/jp5b05433_si_001.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "An, Ni; Zhuang, Bilin; et el." }, { "id": "https://authors.library.caltech.edu/records/83r5y-rs592", "eprint_id": 58999, "eprint_status": "archive", "datestamp": "2023-08-20 07:22:45", "lastmod": "2023-10-23 19:57:39", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Webb-Michael-A", "name": { "family": "Webb", "given": "Michael A." }, "orcid": "0000-0002-7420-4474" }, { "id": "Jung-Yukyung", "name": { "family": "Jung", "given": "Yukyung" } }, { "id": "Pesko-Danielle-M", "name": { "family": "Pesko", "given": "Danielle M." }, "orcid": "0000-0002-4833-0119" }, { "id": "Savoie-Brett-M", "name": { "family": "Savoie", "given": "Brett M." }, "orcid": "0000-0002-7039-4039" }, { "id": "Yamamoto-Umi", "name": { "family": "Yamamoto", "given": "Umi" } }, { "id": "Coates-Geoffrey-W", "name": { "family": "Coates", "given": "Geoffrey W." }, "orcid": "0000-0002-3400-2552" }, { "id": "Balsara-Nitash-P", "name": { "family": "Balsara", "given": "Nitash P." }, "orcid": "0000-0002-0106-5565" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Miller-T-F-III", "name": { "family": "Miller", "given": "Thomas F., III" }, "orcid": "0000-0002-1882-5380" } ] }, "title": "Systematic Computational and Experimental Investigation of Lithium-Ion Transport Mechanisms in Polyester-Based Polymer Electrolytes", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. \n\nReceived: May 21, 2015; Published: July 10, 2015. \n\nThis research was supported by the National Science Foundation under DMREF Award Number NSF-CHE-1335486. M.A.W. also acknowledges support from the Resnick Sustainability Institute.\n\nPublished - acscentsci.5b00195.pdf
Supplemental Material - oc5b00195_si_001.pdf
", "abstract": "Understanding the mechanisms of lithium-ion transport in polymers is crucial for the design of polymer electrolytes. We combine modular synthesis, electrochemical characterization, and molecular simulation to investigate lithium-ion transport in a new family of polyester-based polymers and in poly(ethylene oxide) (PEO). Theoretical predictions of glass-transition temperatures and ionic conductivities in the polymers agree well with experimental measurements. Interestingly, both the experiments and simulations indicate that the ionic conductivity of PEO, relative to the polyesters, is far higher than would be expected from its relative glass-transition temperature. The simulations reveal that diffusion of the lithium cations in the polyesters proceeds via a different mechanism than in PEO, and analysis of the distribution of available cation solvation sites in the various polymers provides a novel and intuitive way to explain the experimentally observed ionic conductivities. This work provides a platform for the evaluation and prediction of ionic conductivities in polymer electrolyte materials.", "date": "2015-07-22", "date_type": "published", "publication": "ACS Central Science", "volume": "1", "number": "4", "publisher": "American Chemical Society", "pagerange": "198-205", "id_number": "CaltechAUTHORS:20150724-073254175", "issn": "2374-7943", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150724-073254175", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1335486" }, { "agency": "Resnick Sustainability Institute" } ] }, "local_group": { "items": [ { "id": "Resnick-Sustainability-Institute" } ] }, "doi": "10.1021/acscentsci.5b00195", "pmcid": "PMC4827473", "primary_object": { "basename": "acscentsci.5b00195.pdf", "url": "https://authors.library.caltech.edu/records/83r5y-rs592/files/acscentsci.5b00195.pdf" }, "related_objects": [ { "basename": "oc5b00195_si_001.pdf", "url": "https://authors.library.caltech.edu/records/83r5y-rs592/files/oc5b00195_si_001.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Webb, Michael A.; Jung, Yukyung; et el." }, { "id": "https://authors.library.caltech.edu/records/n3qd6-29g68", "eprint_id": 56572, "eprint_status": "archive", "datestamp": "2023-08-20 05:30:38", "lastmod": "2023-10-23 15:34:24", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Sing-Michelle-K", "name": { "family": "Sing", "given": "Michelle K." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "McKinley-G-H", "name": { "family": "McKinley", "given": "Gareth H." } }, { "id": "Olsen-B-D", "name": { "family": "Olsen", "given": "Bradley D." } } ] }, "title": "Celebrating Soft Matter's 10th Anniversary: Chain configuration and rate-dependent mechanical properties in transient networks", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 The Royal Society of Chemistry.\n\nReceived 30th September 2014, Accepted 3rd December 2014, First published online 21 Jan 2015.\n\nThis research was supported by the U. S. Army Research Office through the Institute of Soldier Nanotechnologies. M.K.S. was supported by the Department of Defense (DoD) through the National Defense Science and Engineering Graduate Fellowship (NDSEG) Program.\n\nPublished - c4sm02181a.pdf
Supplemental Material - c4sm02181a1.pdf
", "abstract": "Numerical solution of a coupled set of Smoluchowski convection-diffusion equations of associating polymers modelled as finitely extensible dumbbells enables computation of time-dependent end-to-end distributions for bridged, dangling, and looped chains in three dimensions as a function of associating end-group kinetics. Non-monotonic flow curves which can lead to flow instabilities during shear flow result at low equilibrium constant and high association rate from two complementary phenomena: a decrease in the fraction of elastically active chains with increasing shear rate and non-monotonic extension in the population of elastically active chains. Chain tumbling leads to reformation of bridges, resulting in an increased fraction of bridged chains at high Deborah number and significant reduction in the average bridge chain extension. In the start-up of steady shear, force-activated chain dissociation and chain tumbling cause both stress overshoot and stress ringing behaviour prior to reaching steady state stress values. During stress relaxation following steady shear, chain kinetics and extension mediate both the number of relaxations and the length of time required for system relaxation. While at low association rate relaxation is limited by the relaxation of dangling chains and the rate of dangling chain formation, at high association rate coupling of dangling and bridged chains leads to simultaneous relaxation of all chains due to a dynamic equilibrium between dangling and bridged states.", "date": "2015-03-21", "date_type": "published", "publication": "Soft Matter", "volume": "11", "number": "11", "publisher": "Royal Society of Chemistry", "pagerange": "2085-2096", "id_number": "CaltechAUTHORS:20150410-103544942", "issn": "1744-683X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150410-103544942", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Army Research Office (ARO)" }, { "agency": "National Defense Science and Engineering Graduate (NDSEG) Fellowship" } ] }, "doi": "10.1039/c4sm02181a", "primary_object": { "basename": "c4sm02181a.pdf", "url": "https://authors.library.caltech.edu/records/n3qd6-29g68/files/c4sm02181a.pdf" }, "related_objects": [ { "basename": "c4sm02181a1.pdf", "url": "https://authors.library.caltech.edu/records/n3qd6-29g68/files/c4sm02181a1.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Sing, Michelle K.; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/dk38r-cfh67", "eprint_id": 55762, "eprint_status": "archive", "datestamp": "2023-08-20 05:25:11", "lastmod": "2023-10-20 23:08:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "On the theoretical description of weakly charged surfaces", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 AIP Publishing LLC.\n\nReceived 28 November 2014; accepted 23 February 2015; published online 10 March 2015.\n\nAcknowledgment is made to the donors of the American Chemical Society Petroleum Research Fund for partial support of this research.\n\nPublished - 1.4914170.pdf
Submitted - 1502.05265v1.pdf
", "abstract": "It is widely accepted that the Poisson-Boltzmann (PB) theory provides a valid description for charged surfaces in the so-called weak coupling limit. Here, we show that the image charge repulsion creates a depletion boundary layer that cannot be captured by a regular perturbation approach. The correct weak-coupling theory must include the self-energy of the ion due to the image charge interaction. The image force qualitatively alters the double layer structure and properties, and gives rise to many non-PB effects, such as nonmonotonic dependence of the surface energy on concentration and charge inversion. In the presence of dielectric discontinuity, there is no limiting condition for which the PB theory is valid.", "date": "2015-03-14", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "142", "number": "10", "publisher": "American Institute of Physics", "pagerange": "Art. No. 104705", "id_number": "CaltechAUTHORS:20150316-074943499", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150316-074943499", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1063/1.4914170", "primary_object": { "basename": "1.4914170.pdf", "url": "https://authors.library.caltech.edu/records/dk38r-cfh67/files/1.4914170.pdf" }, "related_objects": [ { "basename": "1502.05265v1.pdf", "url": "https://authors.library.caltech.edu/records/dk38r-cfh67/files/1502.05265v1.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/01h0g-3eb72", "eprint_id": 54986, "eprint_status": "archive", "datestamp": "2023-08-20 04:35:18", "lastmod": "2023-10-20 21:13:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Medina-S", "name": { "family": "Medina", "given": "Stefan" } }, { "id": "Zhou-Jiajia", "name": { "family": "Zhou", "given": "Jiajia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Schmid-F", "name": { "family": "Schmid", "given": "Friederike" } } ] }, "title": "An efficient dissipative particle dynamics-based algorithm for simulating electrolyte solutions", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2015 AIP Publishing LLC. Received 29 September 2014. Accepted 16 December 2014. Published online 09 January 2015. \n\nThe authors thank Olga Vinogradova and Aleksey Belyaev for providing the theoretical data and Burkhard D\u00fcnweg for fruitful discussions. This work was funded by the Volkswagen Stiftung. Simulations with explicit ions were performed using the open source program package ESPResSo. Simulations were carried out at the NIC Computing Center J\u00fclich and on the Computer Cluster Mogon at Mainz University.\n\nPublished - 1.4905102.pdf
Submitted - 1412.5008v2.pdf
", "abstract": "We propose an efficient simulation algorithm based on the dissipative particle dynamics (DPD) method for studying electrohydrodynamic phenomena in electrolyte fluids. The fluid flow is mimicked with DPD particles while the evolution of the concentration of the ionic species is described using Brownian pseudo particles. The method is designed especially for systems with high salt concentrations, as explicit treatment of the salt ions becomes computationally expensive. For illustration, we apply the method to electro-osmotic flow over patterned, superhydrophobic surfaces. The results are in good agreement with recent theoretical predictions.", "date": "2015-01-14", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "142", "number": "2", "publisher": "American Institute of Physics", "pagerange": "Art. No. 024103", "id_number": "CaltechAUTHORS:20150219-082241993", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150219-082241993", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Volkswagen Stiftung" } ] }, "doi": "10.1063/1.4905102", "primary_object": { "basename": "1.4905102.pdf", "url": "https://authors.library.caltech.edu/records/01h0g-3eb72/files/1.4905102.pdf" }, "related_objects": [ { "basename": "1412.5008v2.pdf", "url": "https://authors.library.caltech.edu/records/01h0g-3eb72/files/1412.5008v2.pdf" } ], "resource_type": "article", "pub_year": "2015", "author_list": "Medina, Stefan; Zhou, Jiajia; et el." }, { "id": "https://authors.library.caltech.edu/records/330pv-jar21", "eprint_id": 120759, "eprint_status": "archive", "datestamp": "2023-08-22 13:27:49", "lastmod": "2023-10-18 17:59:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Xin-ChemE", "name": { "family": "Wang", "given": "Xin" } }, { "id": "Thelen-Jacob-L", "name": { "family": "Thelen", "given": "Jacob L." } }, { "id": "Teran-Alexander-A", "name": { "family": "Teran", "given": "Alexander A." } }, { "id": "Chintapalli-Mahati", "name": { "family": "Chintapalli", "given": "Mahati" } }, { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Newstein-Maurice-C", "name": { "family": "Newstein", "given": "Maurice C." } }, { "id": "Balsara-Nitash-P", "name": { "family": "Balsara", "given": "Nitash P." }, "orcid": "0000-0002-0106-5565" }, { "id": "Garetz-Bruce-A", "name": { "family": "Garetz", "given": "Bruce A." } } ] }, "title": "Evolution of Grain Structure during Disorder-to-Order Transitions in a Block Copolymer/Salt Mixture Studied by Depolarized Light Scattering", "ispublished": "pub", "full_text_status": "public", "keywords": "Materials Chemistry; Inorganic Chemistry; Polymers and Plastics; Organic Chemistry", "note": "\u00a9 2014 American Chemical Society. \n\nThe authors acknowledge the generous support of the National Science Foundation through Award Numbers DMR-0966626, DMR-0966765, and CBET-0965812. Any opinions, findings, and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the National Science Foundation. The assistance of Mr. Hao-Chun Chiang in solving some programming problems is also appreciated. \n\nThe authors declare no competing financial interest.", "abstract": "Block copolymer/lithium salt mixtures are promising materials for lithium battery electrolytes. The growth of ordered lamellar grains after a block copolymer electrolyte was quenched from the disordered state to the ordered state was studied by depolarized light scattering. Three quench depths below the order-to-disorder transition temperature were studied: 6, 12, and 24 \u00b0C. Regardless of quench depth, elongated ellipsoidal grains with aspect ratios between six and eight were formed during the initial stage of order formation. This was followed by a rapid reduction in aspect ratio; at long times, isotropic grains with aspect ratios in the vicinity of unity were obtained. Unusual grain growth kinetics were observed at all quench depths: (1) The average grain volume decreased with time after the early stage of grain growth. To our knowledge, a decrease in grain size has never been observed before in any quenched block copolymer system. (2) The volume fraction occupied by ordered grains of the shallowest quenched sample (quench depth of 6 \u00b0C) was significantly less than unity even after waiting times approaching 400 min. This is consistent with recent theoretical and experimental work indicating the presence of a coexistence window between ordered and disordered phases due to the partitioning of the salt into the ordered domains. At quench depths of 12 and 24 \u00b0C, which are outside the coexistence window, the grain volume fraction increases monotonically with time, and ordered grains occupy the entire sample at long times.", "date": "2014-08-26", "date_type": "published", "publication": "Macromolecules", "volume": "47", "number": "16", "publisher": "American Chemical Society", "pagerange": "5784-5792", "id_number": "CaltechAUTHORS:20230411-336238000.1", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230411-336238000.1", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0966626" }, { "agency": "NSF", "grant_number": "DMR-0966765" }, { "agency": "NSF", "grant_number": "CBET-0965812" } ] }, "doi": "10.1021/ma501166p", "resource_type": "article", "pub_year": "2014", "author_list": "Wang, Xin; Thelen, Jacob L.; et el." }, { "id": "https://authors.library.caltech.edu/records/qjr43-f7q18", "eprint_id": 49807, "eprint_status": "archive", "datestamp": "2023-08-20 02:17:49", "lastmod": "2023-10-17 22:13:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Thermodynamics of Salt-Doped Block Copolymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society. \n\nReceived: May 19, 2014; Accepted: July 7, 2014; Published: July 10, 2014. \n\nThis research has been supported by the National Science Foundation, Grant Nos. CBET-0965812 and CHE-1040558.", "abstract": "We provide a perspective on the thermodynamics of salt-doped block copolymer electrolytes consisting of ion-conducting and inert blocks, taking poly(ethylene oxide)-b-polystyrene and lithium salts as an example. We focus on the origin for enhanced immiscibility between the constituent blocks upon addition of lithium salts and discuss issues from selected experiments and from our recent self-consistent field study.", "date": "2014-08", "date_type": "published", "publication": "ACS Macro Letters", "volume": "3", "number": "8", "publisher": "American Chemical Society", "pagerange": "708-711", "id_number": "CaltechAUTHORS:20140918-092228450", "issn": "2161-1653", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140918-092228450", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CBET-0965812" }, { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/mz500301z", "resource_type": "article", "pub_year": "2014", "author_list": "Nakamura, Issei and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/kv6sj-dw315", "eprint_id": 48761, "eprint_status": "archive", "datestamp": "2023-08-20 01:53:11", "lastmod": "2023-10-17 20:24:55", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Xiaofei", "name": { "family": "Xu", "given": "Xiaofei" } }, { "id": "Cristancho-D-E", "name": { "family": "Cristancho", "given": "Diego E." } }, { "id": "Costeux-S", "name": { "family": "Costeux", "given": "St\u00e9phane" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nanoparticle Solvation in Polymer\u2013CO_2 Mixtures", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2014 American Chemical Society.\n\nReceived: January 30, 2014; Revised: April 2, 2014; Published: April 3, 2014.\n\nThe Dow Chemical Company is acknowledged for funding and\nfor permission to publish the results. The computing facility on which the calculations were performed is supported by an NSFMRI grant, Award No. CHE-1040558.", "abstract": "We study the solvation of a single nanoparticle in poly(methyl methacrylate)\u2013CO_2 mixture at coexistence by using statistical classical density-functional theory. In the temperature range where there is triple-phase coexistence, the lowest solvation free energy occurs at the triple point pressure. Beyond the end point temperature of the triple line, and for particle radii less than a critical value, there is an optimal pressure in the solvation free energy, as a result of the competition between the creation of nanoparticle\u2013fluid interface and the formation of cavity volume. The optimal pressure decreases with increasing nanoparticle radius or the strength of nanoparticle attraction with the fluid components. The critical radius can be estimated from the pressure dependence of the interfacial tension between the fluid and the particle in the limit of infinitely large particle size (i.e., planar wall).", "date": "2014-07-17", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "118", "number": "28", "publisher": "American Chemical Society", "pagerange": "8002-8007", "id_number": "CaltechAUTHORS:20140821-090639372", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140821-090639372", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1021/jp501083f", "resource_type": "article", "pub_year": "2014", "author_list": "Xu, Xiaofei; Cristancho, Diego E.; et el." }, { "id": "https://authors.library.caltech.edu/records/rtwc1-3h957", "eprint_id": 47708, "eprint_status": "archive", "datestamp": "2023-08-20 01:31:30", "lastmod": "2023-10-26 21:11:03", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Theory of Polymer Chains in Poor Solvent: Single-Chain Structure, Solution Thermodynamics, and \u0398 Point", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society.\n\nReceived: February 25, 2014;\nRevised: June 4, 2014;\nPublished: June 13, 2014.\n\nThe computing facility on which the calculations were\nperformed is supported by an NSF-MRI grant, Award No.\nCHE-1040558.\n\nSubmitted - 1406.1246v1.pdf
", "abstract": "Using the language of the Flory \u03c7 parameter, we develop a theory that unifies the treatment of the single-chain structure and the solution thermodynamics of polymers in poor solvents. The structure of a globule and its melting thermodynamics is examined using the self-consistent filed theory. Our results show that the chain conformation involves three states prior to the globule-to-coil transition: the fully collapsed globule, the swollen globule, and the molten globule, which are distinguished by the core density and the interfacial thickness. By examining the chain-length dependence of the melting of the swollen globule, we find universal scaling behavior in the chain properties near the \u0398 point. The information on density profile and free energy of the globule is used in the dilute solution thermodynamics to study the phase equilibrium of polymer solution. Our results show different scaling behavior of the solubility of polymers in the dilute solution compared to the F\u2013H theory, both in the \u03c7 dependence and in the chain-length dependence. From the perspectives of single chain structure and solution thermodynamics, our results verify the consistency of the \u0398 point defined by different criteria in the limit of infinite chain length: the disappearance of the effective two-body interaction, the abrupt change in chain size, and the critical point in the phase diagram of the polymer solution. Our results show \u03c7_\u0398 = 0.5 (for the case of equal monomer and solvent volume), which coincides with the value predicted from the F\u2013H theory.", "date": "2014-06-24", "date_type": "published", "publication": "Macromolecules", "volume": "47", "number": "12", "publisher": "American Chemical Society", "pagerange": "4094-4102", "id_number": "CaltechAUTHORS:20140731-113937619", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140731-113937619", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1021/ma5003968", "primary_object": { "basename": "1406.1246v1.pdf", "url": "https://authors.library.caltech.edu/records/rtwc1-3h957/files/1406.1246v1.pdf" }, "resource_type": "article", "pub_year": "2014", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/afyz6-x3q42", "eprint_id": 46033, "eprint_status": "archive", "datestamp": "2023-08-20 00:27:57", "lastmod": "2023-10-26 18:37:52", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Thelen-J-L", "name": { "family": "Thelen", "given": "Jacob L." } }, { "id": "Teran-A-A", "name": { "family": "Teran", "given": "Alexander A." } }, { "id": "Wang-Xin", "name": { "family": "Wang", "given": "Xin" }, "orcid": "0000-0002-6180-0058" }, { "id": "Garetz-B-A", "name": { "family": "Garetz", "given": "Bruce A." } }, { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Balsara-N-P", "name": { "family": "Balsara", "given": "Nitash P." }, "orcid": "0000-0002-0106-5565" } ] }, "title": "Phase Behavior of a Block Copolymer/Salt Mixture through the Order-to-Disorder Transition", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Chemical Society. Received: February 6, 2014.\nRevised: March 17, 2014. Published: April 2, 2014. Publication Date (Web): April 2, 2014. This work was supported by the National Science Foundation,\nGrants DMR-0966626 and DMR-0966765. SAXS experiments\nwere performed at Lawrence Berkeley National Laboratory's\nAdvance Light Source, Beamline 7.3.3. Beamline 7.3.3 of the\nAdvanced Light Source is supported by the Director of the\nOffice of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.\n\nSupplemental Material - ma500292n_si_001.pdf
", "abstract": "Mixtures of block copolymers and lithium salts are promising candidates for lithium battery electrolytes. Structural changes that occur during the order-to-disorder transition (ODT) in a diblock copolymer/salt mixture were characterized by small-angle X-ray scattering (SAXS). In salt-free block copolymers, the ODT is sharp, and the domain size of the ordered phase decreases with increasing temperature. In contrast, the ODT of the diblock copolymer/salt mixture examined here occurs gradually over an 11 \u00b0C temperature window, and the domain size of the ordered phase is a nonmonotonic function of temperature. We present an approach to estimate the fraction of the ordered phase in the 11 \u00b0C window where ordered and disordered phases coexist. The domain spacing of the ordered phase increases with increasing temperature in the coexistence window. Both findings are consistent with the selective partitioning of salt into the ordered domains, as predicted by Nakamura et al. ( ACS Macro Lett. 2013, 2, 478\u2212481).", "date": "2014-04-22", "date_type": "published", "publication": "Macromolecules", "volume": "47", "number": "8", "publisher": "American Chemical Society", "pagerange": "2666-2673", "id_number": "CaltechAUTHORS:20140602-135911591", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140602-135911591", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0966626" }, { "agency": "NSF", "grant_number": "DMR-0966765" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC02-05CH11231" } ] }, "doi": "10.1021/ma500292n", "primary_object": { "basename": "ma500292n_si_001.pdf", "url": "https://authors.library.caltech.edu/records/afyz6-x3q42/files/ma500292n_si_001.pdf" }, "resource_type": "article", "pub_year": "2014", "author_list": "Thelen, Jacob L.; Teran, Alexander A.; et el." }, { "id": "https://authors.library.caltech.edu/records/984fg-f5s49", "eprint_id": 46008, "eprint_status": "archive", "datestamp": "2023-08-20 00:20:27", "lastmod": "2023-10-26 18:36:38", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Continuous Self-Energy of Ions at the Dielectric Interface", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2014 American Physical Society.\n\nReceived 20 October 2013; published 2 April 2014.\n\nAcknowledgment is made to the donors of the American\nChemical Society Petroleum Research Fund for partial\nsupport of this research. We thank Professor Yan Levin for\nmany helpful discussions.\n\nPublished - PhysRevLett.112.136101.pdf
Submitted - 1310.8274v2.pdf
", "abstract": "By treating both the short-range (solvation) and long-range (image force) electrostatic forces as well as charge polarization induced by these forces in a consistent manner, we obtain a simple theory for the self-energy of an ion that is continuous across the interface. Along with nonelectrostatic contributions, our theory enables a unified description of ions on both sides of the interface. Using intrinsic parameters of the ions, we predict the specific ion effect on the interfacial affinity of halogen anions at the water-air interface, and the strong adsorption of hydrophobic ions at the water-oil interface, in agreement with experiments and atomistic simulations.", "date": "2014-04-04", "date_type": "published", "publication": "Physical Review Letters", "volume": "112", "number": "13", "publisher": "American Physical Society", "pagerange": "Art. No. 136101", "id_number": "CaltechAUTHORS:20140530-110321209", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140530-110321209", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1103/PhysRevLett.112.136101", "primary_object": { "basename": "1310.8274v2.pdf", "url": "https://authors.library.caltech.edu/records/984fg-f5s49/files/1310.8274v2.pdf" }, "related_objects": [ { "basename": "PhysRevLett.112.136101.pdf", "url": "https://authors.library.caltech.edu/records/984fg-f5s49/files/PhysRevLett.112.136101.pdf" } ], "resource_type": "article", "pub_year": "2014", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/kntr4-xvr51", "eprint_id": 44642, "eprint_status": "archive", "datestamp": "2023-08-20 00:06:32", "lastmod": "2023-10-26 14:50:30", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Xiaofei", "name": { "family": "Xu", "given": "Xiaofei" } }, { "id": "Ting-Christina-L", "name": { "family": "Ting", "given": "Christina L." } }, { "id": "Kusaka-Isamu", "name": { "family": "Kusaka", "given": "Isamu" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nucleation in Polymers and Soft Matter", "ispublished": "pub", "full_text_status": "restricted", "keywords": "minimum free energy path, binary mixtures, microphase separation,\nmembrane fusion, membrane pore formation, membrane rupture", "note": "\u00a9 2014 by Annual Reviews.\nX.X. thanks Dr. Ran Ni for helpful discussions about the umbrella sampling method. Sandia\nNational Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation,\na wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's\nNational Nuclear Security Administration under contract DE-AC04-94AL85000.", "abstract": "Nucleation is a ubiquitous phenomenon in many physical, chemical, and\nbiological processes. In this review, we describe recent progress on the theoretical\nstudy of nucleation in polymeric fluids and soft matter, including\nbinary mixtures (polymer blends, polymers in poor solvents, compressible\npolymer\u2013small molecule mixtures), block copolymer melts, and lipid membranes.\nWe discuss the methodological development for studying nucleation\nas well as novel insights and new physics obtained in the study of the nucleation\nbehavior in these systems.", "date": "2014-04", "date_type": "published", "publication": "Annual Review of Physical Chemistry", "volume": "65", "publisher": "Annual Reviews", "pagerange": "449-475", "id_number": "CaltechAUTHORS:20140403-133743029", "issn": "0066-426X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140403-133743029", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE) National Nuclear Security Administration", "grant_number": "DE-AC04-94AL85000" } ] }, "doi": "10.1146/annurev-physchem-032511-143750", "resource_type": "article", "pub_year": "2014", "author_list": "Xu, Xiaofei; Ting, Christina L.; et el." }, { "id": "https://authors.library.caltech.edu/records/dyt4s-er336", "eprint_id": 42166, "eprint_status": "archive", "datestamp": "2023-08-19 21:33:56", "lastmod": "2023-10-25 15:42:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of image charges on double layer structure and forces", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 AIP Publishing LLC.\nReceived 30 March 2013; accepted 4 September 2013; published online 24 September 2013.\n\nPublished - 1.4821636.pdf
", "abstract": "The study of the electrical double layer lies at the heart of soft matter physics and biophysics. Here, we address the effects of the image charges on the double layer structure and forces. For electrolyte solutions between two neutral plates, we show that depletion of the salt ions by the image charge repulsion results in short-range attractive and long-range repulsive forces. If cations and anions are of different valency, the asymmetric depletion leads to the formation of an induced electrical double layer. In comparison to a 1:1 electrolyte solution, both the attractive and the repulsive parts of the interaction are stronger for the 2:1 electrolyte solution. For two charged plates, the competition between the surface charge and the image charge effect can give rise to like-charge attraction and charge inversion. These results are in stark contrast with predictions from the Poisson-Boltzmann theory.", "date": "2013-09-28", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "139", "number": "12", "publisher": "American Institute of Physics", "pagerange": "Art. No. 124702", "id_number": "CaltechAUTHORS:20131101-074353722", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131101-074353722", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1063/1.4821636", "primary_object": { "basename": "1.4821636.pdf", "url": "https://authors.library.caltech.edu/records/dyt4s-er336/files/1.4821636.pdf" }, "resource_type": "article", "pub_year": "2013", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/j9c2z-hkm74", "eprint_id": 41138, "eprint_status": "archive", "datestamp": "2023-08-19 20:49:54", "lastmod": "2023-10-24 23:28:54", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Intrinsic Viscosity of Polymers: General Theory Based on a Partially Permeable Sphere Model", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2013 American Chemical Society.\n\nReceived: April 28, 2013;\nRevised: June 24, 2013;\nPublished: July 2, 2013.\n\nThis work is supported, in part, by the National Natural Science\nFoundation of China (No. 21120102037) and further\nsubsidized by the Special Funds for National Basic Research\nProgram of China (No. 2012CB821500).", "abstract": "We present a general theory for the intrinsic viscosity of flexible polymers of arbitrary architecture. The theory is based on a partially permeable sphere model for which we introduce two phenomenological functions, the drag function \u03be and the drainage function \u03ba, that are determined by the density profile of the polymer. At the mean-field level, these functions capture the long-range, multibody, accumulative hydrodynamic interactions, that are responsible for the frictional dissipation in and around a polymer. The density profiles for a diversity of chain architectures are obtained by Monte Carlo simulation. Predictions from our theory are in good agreement with experimental data on all the polymer structures examined, ranging from linear, ring, and stars to hyperbranched and dendrimers. The concepts and methods we introduce in this work should be useful for studying other dilute solution frictional properties, such as the self-diffusivity, and provide a convenient framework for understanding the relationship between the molecular architecture and their dilute solution properties.", "date": "2013-07-23", "date_type": "published", "publication": "Macromolecules", "volume": "46", "number": "14", "publisher": "American Chemical Society", "pagerange": "5731-5740", "id_number": "CaltechAUTHORS:20130906-092122971", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130906-092122971", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "21120102037" }, { "agency": "Special Funds for National Basic Research Program of China", "grant_number": "2012CB821500" } ] }, "doi": "10.1021/ma400872s", "resource_type": "article", "pub_year": "2013", "author_list": "Lu, Yuyuan; An, Lijia; et el." }, { "id": "https://authors.library.caltech.edu/records/vwe8h-b8r42", "eprint_id": 41348, "eprint_status": "archive", "datestamp": "2023-08-19 20:11:07", "lastmod": "2023-10-24 23:40:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Balsara-N-P", "name": { "family": "Balsara", "given": "Nitash P." }, "orcid": "0000-0002-0106-5565" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "First-Order Disordered-to-Lamellar Phase Transition in Lithium Salt-Doped Block Copolymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2013 American Chemical Society.\n\nReceived: March 22, 2013;\nAccepted: May 13, 2013;\nPublished: May 16, 2013.\n\nThis research has been supported by the National Science\nFoundation, Grants No. CBET-0965812 and No. CHE-1040558.", "abstract": "We study the microphase separation of block copolymer electrolytes containing lithium salts. Taking poly(ethylene oxide)-b-polystyrene (PEO-b-PS) as an example, we show that in the presence of lithium salts the disordered-to-lamellar phase transition becomes first-order even at the level of mean-field theory, with a moderate range of temperature in which both the disordered and lamellar phases coexist, and different salt concentration in the coexisting phases. The coexistence arises from the different partitioning of the salt ions between the disordered phase and the lamellar phase, driven primarily by the solvation energy of anions. A striking consequence of the coexistence is that heating a lamellar phase into the coexistence region leads to increased order in the remaining lamellar phase.", "date": "2013-06", "date_type": "published", "publication": "ACS Macro Letters", "volume": "2", "number": "6", "publisher": "American Chemical Society", "pagerange": "478-481", "id_number": "CaltechAUTHORS:20130916-150307749", "issn": "2161-1653", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130916-150307749", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CBET-0965812" }, { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1021/mz4001404", "resource_type": "article", "pub_year": "2013", "author_list": "Nakamura, Issei; Balsara, Nitash P.; et el." }, { "id": "https://authors.library.caltech.edu/records/fsst5-31883", "eprint_id": 39330, "eprint_status": "archive", "datestamp": "2023-08-19 19:58:07", "lastmod": "2023-10-24 16:41:33", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of dielectric inhomogeneity in polyelectrolyte solutions", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 The Royal Society of Chemistry.\nReceived 3rd March 2013;\nAccepted 25th April 2013.\nFirst published online 20 May 2013.\nThis research has been supported by the National Science\nFoundation, Grant no. CBET-0965812 and CHE-1040558.\n\nPublished - c3sm50632k.pdf
", "abstract": "We illustrate the effects of dielectric inhomogeneity on the statistical properties of polyelectrolytes in solution, by a lattice Monte Carlo simulation that combines the bond fluctuation model with a local algorithm for computing the electrostatic interactions. Our model accounts for the difference in the dielectric properties between the polymer backbone and the solvent. Taking the coil\u2013globule transition of a single polyelectrolyte chain in solvent as an example, we show that the chain conformation and the degree of counterion condensation are substantially affected by the dielectric contrast.", "date": "2013-05-20", "date_type": "published", "publication": "Soft Matter", "volume": "9", "number": "24", "publisher": "Royal Society of Chemistry", "pagerange": "5686-5690", "id_number": "CaltechAUTHORS:20130712-081405274", "issn": "1744-683X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130712-081405274", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CBET-0965812" }, { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1039/c3sm50632k", "primary_object": { "basename": "c3sm50632k.pdf", "url": "https://authors.library.caltech.edu/records/fsst5-31883/files/c3sm50632k.pdf" }, "resource_type": "article", "pub_year": "2013", "author_list": "Nakamura, Issei and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/q2477-vtq10", "eprint_id": 39954, "eprint_status": "archive", "datestamp": "2023-08-19 19:57:39", "lastmod": "2023-10-24 17:20:12", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Xiaofei", "name": { "family": "Xu", "given": "Xiaofei" } }, { "id": "Cristancho-D-E", "name": { "family": "Cristancho", "given": "Diego E." } }, { "id": "Costeux-S", "name": { "family": "Costeux", "given": "St\u00e9phane" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Discontinuous Bubble Nucleation Due to a Metastable Condensation Transition in Polymer-CO_2 Mixtures", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 American Chemical Society.\n\nReceived: March 11, 2013;\nAccepted: April 26, 2013;\nPublished: April 26, 2013.\n\nThe Dow Chemical Company is acknowledged for funding and\nfor permission to publish the results. The computing facility on\nwhich the calculations were performed is supported by an NSF-MRI\ngrant, Award No. CHE-1040558.\n\nSupplemental Material - jz4005575_si_001.zip
", "abstract": "We combine a newly developed density-functional theory with the string method to calculate the minimum free energy path of bubble nucleation in compressible polymer\u2013CO_2 mixtures. Nucleation is initiated by saturating the polymer liquid with high pressure CO_2 and subsequently reducing the pressure to ambient condition. Below a critical temperature, we find that there is a discontinuous drop in the nucleation barrier with increased initial CO_2 pressure, as a result of an underlying metastable transition from a CO_2-rich-vapor phase to a CO_2-rich-liquid phase. This phenomenon is different from previously proposed nucleation mechanisms involving metastable transitions.", "date": "2013-05-16", "date_type": "published", "publication": "Journal of Physical Chemistry Letters", "volume": "4", "number": "10", "publisher": "American Chemical Society", "pagerange": "1639-1643", "id_number": "CaltechAUTHORS:20130815-134341407", "issn": "1948-7185", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130815-134341407", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1021/jz4005575", "primary_object": { "basename": "jz4005575_si_001.zip", "url": "https://authors.library.caltech.edu/records/q2477-vtq10/files/jz4005575_si_001.zip" }, "resource_type": "article", "pub_year": "2013", "author_list": "Xu, Xiaofei; Cristancho, Diego E.; et el." }, { "id": "https://authors.library.caltech.edu/records/5swpe-njy80", "eprint_id": 42070, "eprint_status": "archive", "datestamp": "2023-08-19 14:00:21", "lastmod": "2023-10-25 15:04:57", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Xiaofei", "name": { "family": "Xu", "given": "Xiaofei" } }, { "id": "Cristancho-D-E", "name": { "family": "Cristancho", "given": "Diego E." } }, { "id": "Costeux-S", "name": { "family": "Costeux", "given": "St\u00e9phane" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Bubble nucleation in polymer\u2013CO_2 mixtures", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2013 The Royal Society of Chemistry.\n\nReceived 26th May 2013; Accepted 3rd August 2013.\n\nThe Dow Chemical Company is acknowledged for funding and\nfor permission to publish the results. The computing facility on which the calculations were performed is supported by an NSFMRI grant, Award no. CHE-1040558.\n\nPublished - c3sm51477c.pdf
", "abstract": "We combine density-functional theory with the string method to calculate the minimum free energy path of bubble nucleation in two polymer\u2013CO_2 mixture systems, poly(methyl methacrylate) (PMMA)\u2013CO_2 and polystyrene (PS)\u2013CO_2. Nucleation is initiated by saturating the polymer liquid with high pressure CO_2 and subsequently reducing the pressure to ambient condition. Below a critical temperature (Tc), we find that there is a discontinuous drop in the nucleation barrier as a function of increased initial CO_2 pressure (P0), as a result of an underlying metastable transition from a CO_2-rich-vapor phase to a CO_2-rich-liquid phase. The nucleation barrier is generally higher for PS\u2013CO_2 than for PMMA\u2013CO_2 under the same temperature and pressure conditions, and both higher temperature and higher initial pressure are required to lower the nucleation barrier for PS\u2013CO2 to experimentally relevant ranges. Classical nucleation theory completely fails to capture the structural features of the bubble nucleus and severely underestimates the nucleation barrier.", "date": "2013", "date_type": "published", "publication": "Soft Matter", "volume": "9", "number": "40", "publisher": "Royal Society of Chemistry", "pagerange": "9675-9683", "id_number": "CaltechAUTHORS:20131025-104557519", "issn": "1744-683X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131025-104557519", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1039/c3sm51477c", "primary_object": { "basename": "c3sm51477c.pdf", "url": "https://authors.library.caltech.edu/records/5swpe-njy80/files/c3sm51477c.pdf" }, "resource_type": "article", "pub_year": "2013", "author_list": "Xu, Xiaofei; Cristancho, Diego E.; et el." }, { "id": "https://authors.library.caltech.edu/records/a92wt-ms435", "eprint_id": 36760, "eprint_status": "archive", "datestamp": "2023-08-19 13:53:56", "lastmod": "2023-10-23 15:28:15", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Shi-An-Chang", "name": { "family": "Shi", "given": "An-Chang" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Ion Solvation in Liquid Mixtures: Effects of Solvent Reorganization", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Physical Society.\n\nReceived 26 July 2012; published 20 December 2012.\n\nThis research has been supported by the National Science Foundation, Grants No. CBET-0965812 and No. CHE-1040558, and by the Natural Sciences and Engineering Research Council of Canada (NSERC).\n\nPublished - PhysRevLett.109.257802.pdf
Supplemental Material - README.TXT
Supplemental Material - supplementary_material.pdf
", "abstract": "Using field-theoretic techniques, we study the solvation of salt ions in liquid mixtures, accounting for the permanent and induced dipole moments, as well as the molecular volume of the species. With no adjustable parameters, we predict solvation energies in both single-component liquids and binary liquid mixtures that are in excellent agreement with experimental data. Our study shows that the solvation energy of an ion is largely determined by the local response of the permanent and induced dipoles, as well as the local solvent composition in the case of mixtures, and does not simply correlate with the bulk dielectric constant. In particular, we show that, in a binary mixture, it is possible for the component with the lower bulk dielectric constant but larger molecular polarizability to be enriched near the ion.", "date": "2012-12-21", "date_type": "published", "publication": "Physical Review Letters", "volume": "109", "number": "25", "publisher": "American Physical Society", "pagerange": "Art. No. 257802", "id_number": "CaltechAUTHORS:20130204-114214911", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130204-114214911", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CBET-0965812" }, { "agency": "NSF", "grant_number": "CHE-1040558" }, { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" } ] }, "doi": "10.1103/PhysRevLett.109.257802", "primary_object": { "basename": "supplementary_material.pdf", "url": "https://authors.library.caltech.edu/records/a92wt-ms435/files/supplementary_material.pdf" }, "related_objects": [ { "basename": "PhysRevLett.109.257802.pdf", "url": "https://authors.library.caltech.edu/records/a92wt-ms435/files/PhysRevLett.109.257802.pdf" }, { "basename": "README.TXT", "url": "https://authors.library.caltech.edu/records/a92wt-ms435/files/README.TXT" } ], "resource_type": "article", "pub_year": "2012", "author_list": "Nakamura, Issei; Shi, An-Chang; et el." }, { "id": "https://authors.library.caltech.edu/records/zabaq-cv312", "eprint_id": 36078, "eprint_status": "archive", "datestamp": "2023-08-19 13:08:46", "lastmod": "2023-10-20 22:13:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ting-Christina-L", "name": { "family": "Ting", "given": "Christina L." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Minimum free energy paths for a nanoparticle crossing the lipid membrane", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 Royal Society of Chemistry.\n\nReceived 13th June 2012; accepted 14th September 2012.\nFirst published on the web 10 Oct 2012.\nThe authors would like to thank Daniel Appel\u00f6 for many helpful discussions. This work was supported by the Joseph J. Jacobs Institute for Molecular Engineering for Medicine and by a Sandia National Laboratory Fellowship to C.L.T. The\ncomputing facility on which the calculations were performed is\nsupported by an NSF-MRI grant, Award no. CHE-1040558.\n\nPublished - c2sm26377g.pdf
", "abstract": "Within self-consistent field theory, we develop an \"on-the-fly\" string method to compute the minimum free energy path for several activated processes involving a charged, solvophobic nanoparticle and a lipid membrane. Under tensions well below the mechanical stability limit of the membrane, and in the regime where the event can occur on experimentally relevant time scales, our study suggests that there can be at least three competing pathways for crossing the membrane: (1) particle-assisted membrane rupture, (2) particle insertion into a metastable pore followed by translocation and membrane resealing, and (3) particle insertion into a metastable pore followed by membrane rupture. In the context of polymer-based gene delivery systems, we discuss the implications of these results for the endosomal escape mechanism.", "date": "2012-10-10", "date_type": "published", "publication": "Soft Matter", "volume": "8", "number": "48", "publisher": "Royal Society of Chemistry", "pagerange": "12066-12071", "id_number": "CaltechAUTHORS:20121220-114824437", "issn": "1744-683X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121220-114824437", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Joseph J. Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "Sandia National Laboratory Fellowship" }, { "agency": "NSF-MRI grant", "grant_number": "CHE-1040558" } ] }, "doi": "10.1039/c2sm26377g", "primary_object": { "basename": "c2sm26377g.pdf", "url": "https://authors.library.caltech.edu/records/zabaq-cv312/files/c2sm26377g.pdf" }, "resource_type": "article", "pub_year": "2012", "author_list": "Ting, Christina L. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/d9v81-3r119", "eprint_id": 34348, "eprint_status": "archive", "datestamp": "2023-09-14 19:33:10", "lastmod": "2023-10-23 20:52:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhuang-Bilin", "name": { "family": "Zhuang", "given": "Bilin" }, "orcid": "0000-0003-2934-4264" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Anomalous Concentration Effects on Phase Behavior and Nematic\n Order in Mixtures of Side-Chain Liquid Crystal Polymers and Low-Molecular-Weight Liquid Crystals", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society.\n\nReceived: March 30, 2012; Revised: May 30, 2012; Published: July 18, 2012.\n\nWe thank Rui Wang for helpful discussions. This work was\nsupported by the NSF under Grant CHE-1040558, and B.Z.\ngratefully acknowledges support as an A-STAR fellow.\n\nPublished - ma300657s.pdf
", "abstract": "We study the anomalous concentration effects in mixtures of side-chain liquid crystalline polymers (SCLCPs) and low-molecular-weight liquid crystals (LMWLCs) by modifying the theory of Brochard, Jouffroy, and Levinson (BJL) to include the effects of the polymer backbone. Our new theory considers both the interaction of the polymer backbone with the global nematic field, as well as the local steric constraints due to the grafting of the side groups onto the polymer backbone. In addition, we consider the enhancement in the coupling between the pedant mesogens and the LMWLC molecules as the SCLCP concentration increases. The resulting phase diagram and nematic order parameters are in qualitative agreement with experimental observations, but drastically different from the predictions by the BJL theory.", "date": "2012-08-14", "date_type": "published", "publication": "Macromolecules", "volume": "45", "number": "15", "publisher": "American Chemical Society", "pagerange": "6220-6229", "id_number": "CaltechAUTHORS:20120925-105542854", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120925-105542854", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1040558" }, { "agency": "Agency for Science, Technology and Research (A*STAR)" } ] }, "doi": "10.1021/ma300657s", "primary_object": { "basename": "ma300657s.pdf", "url": "https://authors.library.caltech.edu/records/d9v81-3r119/files/ma300657s.pdf" }, "resource_type": "article", "pub_year": "2012", "author_list": "Zhuang, Bilin and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/k1pqr-9bz03", "eprint_id": 34463, "eprint_status": "archive", "datestamp": "2023-09-14 19:33:59", "lastmod": "2023-10-23 20:53:05", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Theory of Polymers in Poor Solvent: Phase Equilibrium and\n Nucleation Behavior", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 American Chemical Society.\n\nReceived: May 22, 2012; Revised: July 14, 2012; Published: July 24, 2012.\n\nThis work is in part supported by the National Science\nFoundation through MRSEC-CALTECH, and in part supported by NSF Grant No. CHE-1040558.\n\nPublished - ma301049m.pdf
", "abstract": "We study the phase equilibrium and nucleation behavior of polymers in poor solvent by accounting for the large, localized fluctuations in the form of single-chain globules and multichain clusters. The density profile and free energy of the single-chain globule and multichain clusters are obtained by self-consistent-field theory. This information is then used in the dilute solution thermodynamics to investigate the equilibrium cluster size distribution, solubility limit, and nucleation in the supersaturated state. Our results show that the solubility of the polymer in the dilute side of the solution is enhanced by several orders of magnitude relative to the prediction of the Flory\u2013Huggins (F\u2013H) theory, which scales with the chain length to the 2/3 power rather than a linear power as predicted from the F\u2013H theory. Our results also suggest a higher critical value of \u03c7, consistent with computer simulation and experiment results. In the supersaturated state, we work out an effective spinodal where the nucleation barrier to phase separation via growth of the clusters becomes comparable to the thermal energy k_(B)T. For a given supersaturation, we find that the nucleation barrier is quadratic in the chain length, suggesting a much slower precipitation rate for longer polymer chains.", "date": "2012-08-14", "date_type": "published", "publication": "Macromolecules", "volume": "45", "number": "15", "publisher": "American Chemical Society", "pagerange": "6266-6271", "id_number": "CaltechAUTHORS:20120926-114840182", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120926-114840182", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1021/ma301049m", "primary_object": { "basename": "ma301049m.pdf", "url": "https://authors.library.caltech.edu/records/k1pqr-9bz03/files/ma301049m.pdf" }, "resource_type": "article", "pub_year": "2012", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/zrs22-5mf72", "eprint_id": 35487, "eprint_status": "archive", "datestamp": "2023-08-22 06:22:58", "lastmod": "2023-10-20 16:24:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Xiaofei", "name": { "family": "Xu", "given": "Xiaofei" } }, { "id": "Cristancho-D-E", "name": { "family": "Cristancho", "given": "Diego E." } }, { "id": "Costeux-S", "name": { "family": "Costeux", "given": "St\u00e9phane" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Density-functional theory for polymer-carbon dioxide mixtures: A perturbed-chain SAFT approach", "ispublished": "pub", "full_text_status": "public", "keywords": "carbon compounds; density functional theory; equations of state; free energy; high-pressure effects; interface phenomena; mixtures; polymers; solubility; statistical analysis; surface tension", "note": "\u00a9 2012 American Institute of Physics.\n\nReceived 12 June 2012; accepted 20 July 2012; published online 7 August 2012.\n\nThe Dow Chemical Company is acknowledged for funding\nand for permission to publish the results. The computing\nfacility on which the calculations were performed is supported by an NSF-MRI grant, Award No. CHE-1040558.\n\nPublished - JChemPhys_137_054902.pdf
", "abstract": "We propose a density-functional theory (DFT) describing inhomogeneous polymer-carbon dioxide mixtures based on a perturbed-chain statistical associating fluid theory equation of state (PC-SAFT EOS). The weight density functions from fundamental measure theory are used to extend the bulk excess Helmholtz free energy to the inhomogeneous case. The additional long-range dispersion contributions are included using a mean-field approach. We apply our DFT to the interfacial properties of polystyrene-CO_2 and poly(methyl methacrylate) CO_2 systems. Calculated values for both solubility and interfacial tension are in good agreement with experimental data. In comparison with our earlier DFT based on the Peng-Robinson-SAFT EOS, the current DFT produces quantitatively superior agreement with experimental data and is free of the unphysical behavior at high pressures (>35 MPa) in the earlier theory.", "date": "2012-08-07", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "137", "number": "5", "publisher": "American Institute of Physics", "pagerange": "Art. No. 054902", "id_number": "CaltechAUTHORS:20121115-103218482", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121115-103218482", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" }, { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1063/1.4742346", "primary_object": { "basename": "JChemPhys_137_054902.pdf", "url": "https://authors.library.caltech.edu/records/zrs22-5mf72/files/JChemPhys_137_054902.pdf" }, "resource_type": "article", "pub_year": "2012", "author_list": "Xu, Xiaofei; Cristancho, Diego E.; et el." }, { "id": "https://authors.library.caltech.edu/records/zrxdv-gny04", "eprint_id": 34605, "eprint_status": "archive", "datestamp": "2023-08-19 11:43:53", "lastmod": "2023-10-19 21:19:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Salt-doped block copolymers: ion distribution, domain spacing and effective \u03c7 parameter", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2012 The Royal Society of Chemistry.\n\nReceived 16th March 2012, Accepted 28th May 2012.\nThis research has been supported by the National Science\nFoundation, Grant Nos. CBET-0965812 and CHE-1040558.\n\nPublished - c2sm25606a.pdf
", "abstract": "We develop a self-consistent field theory for salt-doped diblock copolymers, such as polyethylene oxide (PEO)\u2013polystyrene with added lithium salts. We account for the inhomogeneous distribution of Li+ ions bound to the ion-dissolving block, the preferential solvation energy of anions in the different block domains, the translational entropy of anions, the ion-pair equilibrium between polymer-bound Li+ and anion, and changes in the \u03c7 parameter due to the bound ions. We show that the preferential solvation energy of anions provides a large driving force for microphase separation. Our theory is able to explain many features observed in experiments, particularly the systematic dependence in the effective \u03c7-parameter on the radius of the anions, the observed linear dependence in the effective \u03c7 on salt concentration, and increase in the domain spacing of the lamellar phase due to the addition of lithium salts. We also examine the relationship between two definitions of the effective \u03c7 parameter, one based on the domain spacing of the ordered phase and the other based on the structure factor in the disordered phase. We argue that the latter is a more fundamental measure of the effective interaction between the two blocks. We show that the ion distribution and the electrostatic potential profile depend strongly on the dielectric contrast between the two blocks and on the ability of the Li+ to redistribute along the backbone of the ion-dissolving block.", "date": "2012-07-17", "date_type": "published", "publication": "Soft Matter", "volume": "8", "number": "36", "publisher": "Royal Society of Chemistry", "pagerange": "9356-9367", "id_number": "CaltechAUTHORS:20121001-151047732", "issn": "1744-6848", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121001-151047732", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CBET-0965812" }, { "agency": "NSF", "grant_number": "CHE-1040558" } ] }, "doi": "10.1039/c2sm25606a", "primary_object": { "basename": "c2sm25606a.pdf", "url": "https://authors.library.caltech.edu/records/zrxdv-gny04/files/c2sm25606a.pdf" }, "resource_type": "article", "pub_year": "2012", "author_list": "Nakamura, Issei and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/ymkxg-p5952", "eprint_id": 29964, "eprint_status": "archive", "datestamp": "2023-08-19 10:13:16", "lastmod": "2023-10-24 22:37:29", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Xu-Xiaofei", "name": { "family": "Xu", "given": "Xiaofei" } }, { "id": "Cristancho-D-E", "name": { "family": "Cristancho", "given": "Diego E." } }, { "id": "Costeux-S", "name": { "family": "Costeux", "given": "St\u00e9phane" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Density-Functional Theory for Polymer\u2212Carbon Dioxide Mixtures", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2012 American Chemical Society. Received: December 13, 2011\nRevised: February 7, 2012. Accepted: February 9, 2012. Publication Date (Web): February 9, 2012. The Dow Chemical Company is acknowledged for funding and for permission to publish the results.", "abstract": "We propose a new density-functional theory (DFT) describing inhomogeneous polymer\u2013carbon dioxide (CO2) mixtures. The theory is constructed by combining the bulk Peng\u2013Robinson equation of state (PR-EOS) with the statistical associating fluid theory (SAFT) and the fundamental measure theory (FMT). The weight density functions from FMT are used to extend the bulk excess Helmholtz free energy of PR-EOS to the inhomogeneous case, while the SAFT is used to describe correlations due to polymer chain connectivity and short-range forces due to weakly polar or association interactions. The additional long-range dispersion contributions are included using a mean-field approach. We apply our DFT to the interfacial properties of polystyrene\u2013CO_2 and poly(methyl methacrylate)\u2013CO_2 systems. The calculated interfacial tension values are in good agreement with experimental data at low to intermediate pressures. The inclusion of association energy for CO_2 is shown to have a significant effect. We also point out the limitation of the PR-EOS for describing polymer\u2013CO_2 mixtures at high pressures (P > 35 MPa).", "date": "2012-03-07", "date_type": "published", "publication": "Industrial & Engineering Chemistry Research", "volume": "51", "number": "9", "publisher": "American Chemical Society", "pagerange": "3832-3840", "id_number": "CaltechAUTHORS:20120403-134847921", "issn": "0888-5885", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120403-134847921", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Dow Chemical Company" } ] }, "doi": "10.1021/ie2029267", "resource_type": "article", "pub_year": "2012", "author_list": "Xu, Xiaofei; Cristancho, Diego E.; et el." }, { "id": "https://authors.library.caltech.edu/records/db9wz-zmj68", "eprint_id": 31281, "eprint_status": "archive", "datestamp": "2023-08-22 05:04:20", "lastmod": "2023-10-17 15:44:04", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lu-Y-Y", "name": { "family": "Lu", "given": "Y. Y." } }, { "id": "Shi-T-F", "name": { "family": "Shi", "given": "T. F." } }, { "id": "An-L-J", "name": { "family": "An", "given": "L. J." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Intrinsic viscosity of polymers: From linear chains to dendrimers", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Soft matter, liquids and polymers; Fluid dynamics; Chemical physics and physical chemistry", "note": "\u00a9 2012 EPLA.\n\nReceived 14 November 2011; accepted in final form 21 February 2012; published online 21 March 2012.\n\nThis work was supported by the National Natural Science Foundation of China (No. 20734003) and the Fund for Creative Research Groups (No. 50921062), further subsidized by the Special Funds for National Basic Research Program of China (No. 2009CB930100).", "abstract": "We present a simple theory for the intrinsic viscosity of polymers of arbitrary architectures, based on a partially permeable sphere model. The model introduces two phenomenological functions, the drainage function \u03ba(r) and the drag function \u03be(r), which are determined by the density profile, as a mean-field description of the multi-body, long-range and accumulated effects of the hydrodynamic interactions. By combining Debye's theory for free draining polymer chains with Einstein's theory for hard spheres, we arrive at a simple expression for the intrinsic viscosity. Results from our theory show broad agreement in all the key features of the intrinsic viscosity with existing experimental results for polymers ranging from linear chain to branched polymers to dendrimers.", "date": "2012-03", "date_type": "published", "publication": "Europhysics Letters", "volume": "97", "number": "6", "publisher": "IOP", "pagerange": "64003", "id_number": "CaltechAUTHORS:20120502-145603835", "issn": "0295-5075", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120502-145603835", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "20734003" }, { "agency": "Fund for Creative Research Groups", "grant_number": "50921062" }, { "agency": "National Basic Research Program of China Special Funds", "grant_number": "2009CB930100" } ] }, "doi": "10.1209/0295-5075/97/64003", "resource_type": "article", "pub_year": "2012", "author_list": "Lu, Y. Y.; Shi, T. F.; et el." }, { "id": "https://authors.library.caltech.edu/records/qkhpw-9k016", "eprint_id": 28589, "eprint_status": "archive", "datestamp": "2023-08-19 08:35:12", "lastmod": "2023-10-24 18:00:32", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Nakamura-Issei", "name": { "family": "Nakamura", "given": "Issei" }, "orcid": "0000-0002-2701-6913" }, { "id": "Balsara-N-P", "name": { "family": "Balsara", "given": "Nitash P." }, "orcid": "0000-0002-0106-5565" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Thermodynamics of Ion-Containing Polymer Blends and Block Copolymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2011 American Physical Society. Received 19 May 2011; published 1 November 2011.\nThis research has been supported by the National\nScience Foundation, Grant No. CBET-0965812.\n\nPublished - Nakamura2011p16550Phys_Rev_Lett.pdf
Supplemental Material - R2_supplementary.pdf
Supplemental Material - R2_supplementary.tex
Supplemental Material - README.TXT
Supplemental Material - figure_sup.eps
", "abstract": "We develop a theory for the thermodynamics of ion-containing polymer blends and diblock copolymers, taking polyethylene oxide (PEO), polystyrene and lithium salts as an example. We account for the tight binding of Li^+ ions to the PEO, the preferential solvation energy of anions in the PEO domain, the translational entropy of anions, and the ion-pair equilibrium between EO-complexed Li^+ and anion. Our theory is able to predict many features observed in experiments, particularly the systematic dependence in the effective \u03c7 parameter on the size of the anions. Furthermore, comparison with the observed linear dependence in the effective \u03c7 on salt concentration yields an upper limit for the binding constant of the ion pair.", "date": "2011-11-01", "date_type": "published", "publication": "Physical Review Letters", "volume": "107", "number": "19", "publisher": "American Physical Society", "pagerange": "Art. No. 198301", "id_number": "CaltechAUTHORS:20111223-110114533", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111223-110114533", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CBET-0965812" } ] }, "doi": "10.1103/PhysRevLett.107.198301", "primary_object": { "basename": "README.TXT", "url": "https://authors.library.caltech.edu/records/qkhpw-9k016/files/README.TXT" }, "related_objects": [ { "basename": "figure_sup.eps", "url": "https://authors.library.caltech.edu/records/qkhpw-9k016/files/figure_sup.eps" }, { "basename": "Nakamura2011p16550Phys_Rev_Lett.pdf", "url": "https://authors.library.caltech.edu/records/qkhpw-9k016/files/Nakamura2011p16550Phys_Rev_Lett.pdf" }, { "basename": "R2_supplementary.pdf", "url": "https://authors.library.caltech.edu/records/qkhpw-9k016/files/R2_supplementary.pdf" }, { "basename": "R2_supplementary.tex", "url": "https://authors.library.caltech.edu/records/qkhpw-9k016/files/R2_supplementary.tex" } ], "resource_type": "article", "pub_year": "2011", "author_list": "Nakamura, Issei; Balsara, Nitash P.; et el." }, { "id": "https://authors.library.caltech.edu/records/yt678-kxg27", "eprint_id": 27690, "eprint_status": "archive", "datestamp": "2023-08-22 03:56:23", "lastmod": "2023-10-24 17:20:33", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ting-Christina-L", "name": { "family": "Ting", "given": "Christina L." } }, { "id": "Wu-Jianzhong", "name": { "family": "Wu", "given": "Jianzhong" }, "orcid": "0000-0002-4582-5941" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Thermodynamic basis for the genome to capsid charge relationship in viral encapsidation", "ispublished": "pub", "full_text_status": "public", "keywords": "polyelectrolyte; viral assembly", "note": "\u00a9 2011 by the National Academy of Sciences. Edited by David A. Tirrell, California Institute of Technology, Pasadena, CA, and approved August 26, 2011 (received for review June 9, 2011). \nPublished online before print October 3, 2011.\nZ.-G.W. and C.L.T. acknowledge support from the\nJacobs Institute for Molecular Engineering for Medicine at Caltech. C.L.T. is thankful for financial support from an National Institute of Health (NIH)training grant. \nAuthor contributions: J.W. and Z.-G.W. designed research; C.L.T. and Z.-G.W. performed research; C.L.T. and Z.-G.W. analyzed data; and C.L.T. and Z.-G.W. wrote the paper. The authors declare no conflict of interest. This Direct Submission article had a prearranged editor.\n\nPublished - Ting2011p16156P_Natl_Acad_Sci_Usa.pdf
", "abstract": "We establish an appropriate thermodynamic framework for determining the optimal genome length in electrostatically driven viral encapsidation. Importantly, our analysis includes the electrostatic potential due to the Donnan equilibrium, which arises from the semipermeable nature of the viral capsid, i.e., permeable to small mobile ions but impermeable to charged macromolecules. Because most macromolecules in the cellular milieu are negatively charged, the Donnan potential provides an additional driving force for genome encapsidation. In contrast to previous theoretical studies, we find that the optimal genome length is the result of combined effects from the electrostatic interactions of all charged species, the excluded volume and, to a very significant degree, the Donnan potential. In particular, the Donnan potential is essential for obtaining negatively overcharged viruses. The prevalence of overcharged viruses in nature may suggest an evolutionary preference for viruses to increase the amount of genome packaged by utilizing the Donnan potential (through increases in the capsid radius), rather than high charges on the capsid, so that structural stability of the capsid is maintained.", "date": "2011-10-11", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "108", "number": "41", "publisher": "National Academy of Sciences", "pagerange": "16986-16991", "id_number": "CaltechAUTHORS:20111109-073727841", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111109-073727841", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Joseph J. Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "NIH Predoctoral Fellowship" } ] }, "local_group": { "items": [ { "id": "Jacobs-Institute-for-Molecular-Engineering-for-Medicine" } ] }, "doi": "10.1073/pnas.1109307108", "pmcid": "PMC3193252", "primary_object": { "basename": "Ting2011p16156P_Natl_Acad_Sci_Usa.pdf", "url": "https://authors.library.caltech.edu/records/yt678-kxg27/files/Ting2011p16156P_Natl_Acad_Sci_Usa.pdf" }, "resource_type": "article", "pub_year": "2011", "author_list": "Ting, Christina L.; Wu, Jianzhong; et el." }, { "id": "https://authors.library.caltech.edu/records/bg8kb-kx978", "eprint_id": 24674, "eprint_status": "archive", "datestamp": "2023-08-19 07:27:27", "lastmod": "2023-10-23 23:34:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of ion solvation on phase equilibrium and interfacial tension of liquid mixtures", "ispublished": "pub", "full_text_status": "public", "keywords": "dielectric liquids, electrolytes, electrostatics, liquid mixtures, permittivity, phase equilibrium, solubility, solvation, surface tension, thermochemistry", "note": "\u00a9 2011 American Institute of Physics. Received 30 April 2011; accepted 10 June 2011; published online 7 July 2011. This work is in part supported by the National Science\nFoundation through MRSEC-CALTECH.\n\nPublished - Wang2011p15369J_Chem_Phys.pdf
", "abstract": "We study the bulk thermodynamics and interfacial properties of electrolyte solution mixtures by accounting for electrostatic interaction, ion solvation, and inhomogeneity in the dielectric medium in the mean-field framework. Difference in the solvation energy between the cations and anions is shown to give rise to local charge separation near the interface, and a finite Galvani potential between two coexisting solutions. The ion solvation affects the phase equilibrium of the solvent mixture, depending on the dielectric constants of the solvents, reflecting the competition between the solvation energy and translation entropy of the ions. Miscibility is decreased if both solvents have low dielectric constants and is enhanced if both solvents have high dielectric constant. At the mean-field level, the ion distribution near the interface is determined by two competing effects: accumulation in the electrostatic double layer and depletion in a diffuse interface. The interfacial tension shows a nonmonotonic dependence on the salt concentration: it increases linearly with the salt concentration at higher concentrations and decreases approximately as the square root of the salt concentration for dilute solutions, reaching a minimum near 1 mM. We also find that, for a fixed cation type, the interfacial tension decreases as the size of anion increases. These results offer qualitative explanations within one unified framework for the long-known concentration and ion size effects on the interfacial tension of electrolyte solutions.", "date": "2011-07-07", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "135", "number": "1", "publisher": "American Institute of Physics", "pagerange": "Art. No. 014707", "id_number": "CaltechAUTHORS:20110804-092317279", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110804-092317279", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1063/1.3607969", "primary_object": { "basename": "Wang2011p15369J_Chem_Phys.pdf", "url": "https://authors.library.caltech.edu/records/bg8kb-kx978/files/Wang2011p15369J_Chem_Phys.pdf" }, "resource_type": "article", "pub_year": "2011", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/pbys2-9my82", "eprint_id": 24440, "eprint_status": "archive", "datestamp": "2023-08-19 07:14:49", "lastmod": "2023-10-23 22:42:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Guo-Jiayi", "name": { "family": "Guo", "given": "Jiayi" } }, { "id": "Liang-Haojun", "name": { "family": "Liang", "given": "Haojun" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Coil-to-globule transition by dissipative particle dynamics simulation", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2011 American Institute of Physics. Received 26 January 2011; accepted 6 June 2011; published online 30 June 2011. J. Guo gratefully acknowledges the hospitality of the California Institute of Technology, where the work was carried out when she was a visiting student. She is also grateful for the financial support provided by the Program of the National Natural Science Foundation of China (Nos. 20874094, 20934004, and 21004059), NBRPC (No. 2010CB934500),\nand \"Bairen\" fund of CAS.\n\nPublished - Guo2011p14799J_Chem_Phys.pdf
", "abstract": "The dynamics of a collapsing polymer under a temperature quench in dilute solution is investigated by dissipative particles dynamics. Hydrodynamic interactions and many-body interaction are preserved naturally by incorporating explicit solvent particles in this approach. Our simulation suggests a four-stage collapse pathway: localized clusters formation, cluster coarsening in situ, coarsening involving global backbone conformation change into a crumpled globule, and compaction of the globule. For all the quench depths and chain lengths used in our study, collapse proceeds without the chain getting trapped in a metastable \"sausage\" configuration, as reported in some earlier studies. We obtain the time scales for each of the first three stages, as well as its scaling with the quench depths \u03be and chain lengths N. The total collapse time scales as \u03c4_c ~ \u03be^(\u22120.46 \u00b1 0.04)N^(0.98 \u00b1 0.09), with the quench depth and degree of polymerization.", "date": "2011-06-28", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "134", "number": "24", "publisher": "American Institute of Physics", "pagerange": "Art. No. 244904", "id_number": "CaltechAUTHORS:20110718-093610060", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110718-093610060", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Science Foundation of China", "grant_number": "20874094" }, { "agency": "National Science Foundation of China", "grant_number": "20934004" }, { "agency": "National Science Foundation of China", "grant_number": "21004059" }, { "agency": "NBRPC", "grant_number": "2010CB934500" }, { "agency": "CAS" } ] }, "doi": "10.1063/1.3604812", "primary_object": { "basename": "Guo2011p14799J_Chem_Phys.pdf", "url": "https://authors.library.caltech.edu/records/pbys2-9my82/files/Guo2011p14799J_Chem_Phys.pdf" }, "resource_type": "article", "pub_year": "2011", "author_list": "Guo, Jiayi; Liang, Haojun; et el." }, { "id": "https://authors.library.caltech.edu/records/kqr3d-5dj38", "eprint_id": 23787, "eprint_status": "archive", "datestamp": "2023-08-19 06:14:24", "lastmod": "2023-10-23 19:57:28", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ting-Christina-L", "name": { "family": "Ting", "given": "Christina L." } }, { "id": "Appel\u00f6-D", "name": { "family": "Appel\u00f6", "given": "Daniel" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Minimum Energy Path to Membrane Pore Formation and Rupture", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2011 American Physical Society.\n\n\nReceived 12 January 2011; published 18 April 2011.\n\nThis work was supported by the Joseph J. Jacobs\nInstitute of Molecular Engineering for Medicine and the\nNSF Center for the Science and Engineering of Materials\nat Caltech, and by an NIH training grant (to C. L. T.).\n\nPublished - Ting2011p13883Phys_Rev_Lett.pdf
Supplemental Material - README.TXT
Supplemental Material - SupplementaryMaterial.pdf
Supplemental Material - SupplementaryMaterial.tex
", "abstract": "We combine dynamic self-consistent field theory with the string method to calculate the minimum energy path to membrane pore formation and rupture. In the regime where nucleation can occur on experimentally relevant time scales, the structure of the critical nucleus is between a solvophilic stalk and a locally thinned membrane. Classical nucleation theory fails to capture these molecular details and significantly overestimates the free energy barrier. Our results suggest that thermally nucleated rupture may be an important factor for the low rupture strains observed in lipid membranes.", "date": "2011-04-18", "date_type": "published", "publication": "Physical Review Letters", "volume": "106", "number": "16", "publisher": "American Physical Society", "pagerange": "Art. No. 168101", "id_number": "CaltechAUTHORS:20110525-082556253", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110525-082556253", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Joseph J. Jacobs Institute of Molecular Engineering for Medicine" }, { "agency": "NSF" }, { "agency": "NIH" } ] }, "doi": "10.1103/PhysRevLett.106.168101", "primary_object": { "basename": "Ting2011p13883Phys_Rev_Lett.pdf", "url": "https://authors.library.caltech.edu/records/kqr3d-5dj38/files/Ting2011p13883Phys_Rev_Lett.pdf" }, "related_objects": [ { "basename": "README.TXT", "url": "https://authors.library.caltech.edu/records/kqr3d-5dj38/files/README.TXT" }, { "basename": "SupplementaryMaterial.pdf", "url": "https://authors.library.caltech.edu/records/kqr3d-5dj38/files/SupplementaryMaterial.pdf" }, { "basename": "SupplementaryMaterial.tex", "url": "https://authors.library.caltech.edu/records/kqr3d-5dj38/files/SupplementaryMaterial.tex" } ], "resource_type": "article", "pub_year": "2011", "author_list": "Ting, Christina L.; Appel\u00f6, Daniel; et el." }, { "id": "https://authors.library.caltech.edu/records/6bky8-1cf85", "eprint_id": 23054, "eprint_status": "archive", "datestamp": "2023-08-19 05:48:34", "lastmod": "2023-10-23 17:51:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ting-Christina-L", "name": { "family": "Ting", "given": "Christina L." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Interactions of a Charged Nanoparticle with a Lipid Membrane: Implications for Gene Delivery", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2011 Biophysical Society.\n\nReceived 24 September 2010; accepted 23 November 2010. Editor: Ka Yee C. Lee.. Available online 1 March 2011. \n\nThe authors gratefully acknowledge support from the Jacobs Institute for Molecular Engineering for Medicine at Caltech. C.L.T. is thankful for financial support from a National Institutes of Health training grant.", "abstract": "We employ self-consistent field theory to study the thermodynamics of membrane-particle interactions in the context of gene delivery systems, with the aim to guide the design of dendrimers that can overcome the endosomal escape barrier by inserting into membranes and creating pores. We consider the interaction between a model polyamidoamine dendrimer and a membrane under controlled tension as a function of the separation between the dendrimer and the membrane. In all the cases we have studied, the lowest free energy state corresponds to the membrane partially wrapping the dendrimer. However, with moderate tension, we find that a G5 (or larger) generation dendrimer, through thermal fluctuation, can induce the formation of metastable pores. These metastable pores are subsequently shown to significantly lower the critical tension necessary for membrane rupture, thus possibly enhancing the release of the trapped genetic material from the endosome.", "date": "2011-03-02", "date_type": "published", "publication": "Biophysical Journal", "volume": "100", "number": "5", "publisher": "Biophysical Society", "pagerange": "1288-1297", "id_number": "CaltechAUTHORS:20110322-135958575", "issn": "0006-3495", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110322-135958575", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Caltech Jacobs Institute for Molecular Engineering for Medicine" }, { "agency": "NIH" } ] }, "doi": "10.1016/j.bpj.2010.11.042", "resource_type": "article", "pub_year": "2011", "author_list": "Ting, Christina L. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/15v7p-ewj21", "eprint_id": 21608, "eprint_status": "archive", "datestamp": "2023-08-19 04:43:59", "lastmod": "2023-10-21 00:10:48", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Rui", "name": { "family": "Wang", "given": "Rui" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Theory of Side-Chain Liquid Crystal Polymers: Bulk Behavior and Chain Conformation", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2010 American Chemical Society.\nReceived August 8, 2010; Revised Manuscript Received October 19, 2010.\nPublication Date (Web): November 16, 2010.\n\nThis work is supported by the National\nScience Foundation through MRSEC-CALTECH.", "abstract": "We study the thermodynamics and chain conformation of side-chain liquid crystal polymers (SCLCPs) in the bulk using the self-consistent-field approach and a new model to account for the coupling between the orientation of the side-chain liquid-crystal (LC) groups and that of the backbone segments. The new model accounts for both a global coupling between the polymer backbone and the nematic field and a local coupling between the polymer backbone and its attached LC group. Here, the terms global and local refer to the chemical (backbone) distance between the groups. A phenomenological parameter is introduced to represent the coupling strength and nature of the attachment, i.e., end-on vs side-on. The nematic field is shown to control the chain conformation through both the global and the local coupling effects. For the side-on SCLCPs, these two coupling effects act cooperatively so that the chain conformation is always prolate. For the end-on SCLCPs, these two effects act competitively. The chain conformation can be either oblate or prolate in this case, and depends on the relative strengths of these two couplings. On the other hand, the chain conformation also affects the nematic field, primarily through the global coupling. The prolate conformation enhances the nematic field and increases the phase transition temperature, whereas the oblate conformation frustrates the nematic field and decreases the transition temperature. The nematic order parameter is found to be determined mainly by the reduced temperature, and is not sensitive to the coupling effects. Furthermore, we show that the grafting density of the LC side groups has a significant effect on the chain conformation due to the orientational competition between the LC attached and unattached segments. For the end-on SCLCPs with lower graft density, the conformation of the chain backbone can be oblate at higher temperatures and prolate at lower temperatures, in agreement with the re-entrant nematic phase observed in experiments.", "date": "2010-12-14", "date_type": "published", "publication": "Macromolecules", "volume": "43", "number": "23", "publisher": "American Chemical Society", "pagerange": "10096-10106", "id_number": "CaltechAUTHORS:20110105-134943048", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110105-134943048", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1021/ma101805d", "resource_type": "article", "pub_year": "2010", "author_list": "Wang, Rui and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/q4pkx-dg212", "eprint_id": 20579, "eprint_status": "archive", "datestamp": "2023-08-19 04:04:43", "lastmod": "2023-10-20 23:12:53", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wanakule-N-S", "name": { "family": "Wanakule", "given": "Nisita S." } }, { "id": "Virgili-J-M", "name": { "family": "Virgili", "given": "Justin M." } }, { "id": "Teran-A-A", "name": { "family": "Teran", "given": "Alexander A." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Balsara-N-P", "name": { "family": "Balsara", "given": "Nitash P." }, "orcid": "0000-0002-0106-5565" } ] }, "title": "Thermodynamic Properties of Block Copolymer Electrolytes Containing Imidazolium and Lithium Salts", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2010 American Chemical Society.\n\nReceived June 21, 2010; Revised Manuscript Received August 25, 2010. \nPublication Date (Web): September 13, 2010.\n\nThis work was supported by the National Science Foundation (DMR-0966662, CBET-0965812, and CBET-0966632) and the Batteries for Advanced Transportation Technologies (BATT) Program, supported by the U.S. Department of Energy FreedomCAR and Vehicle Technologies Program. N.S.W. was supported by a National Science Foundation Graduate Research Fellowship. The Advanced Light Source is\nsupported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy, under Contract No. DE-AC02-05CH11231. Portions of this research were carried out at the Stanford Synchrotron Radiation Lightsource, a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. We thank Shrayesh Patel for helpful discussions and Ariel Tsui for experimental help.", "abstract": "We report on the thermal properties, phase behavior, and thermodynamics of a series of polystyrene-block-poly(ethylene oxide) copolymers (SEO) mixed with the ionic species Li[N(SO_(2)CF_3)_2] (LiTFSI), imidazolium TFSI (ImTFSI), and an equimolar mixture of LiTFSI and ImTFSI (Mix). Differential scanning calorimetric scans reveal similar thermal behavior of SEO/LiTFSI and SEO/ImTFSI at the same salt concentrations. Phase behavior and thermodynamics were determined using a combination of small-angle X-ray scattering and birefringence. The thermodynamics of our mixtures can be mapped on to the theory of neat block copolymer phase behavior provided the Flory\u2212Huggins interaction parameter, \u03c7, between the blocks is replaced by an effective \u03c7 (\u03c7_(eff)) that increases linearly with salt concentration. The phase behavior and the value of m, the slope of the \u03c7_(eff) versus salt concentration data, were similar for SEO/LiTFSI, SEO/ImTFSI, and SEO/Mix blends. The theory developed by Wang [ J. Phys. Chem. B. 2008, 41, 16205] provides a basis for understanding the fundamental underpinnings of the measured value of m. We compare our experimental results with the predictions of this theory with no adjustable parameters.", "date": "2010-10-12", "date_type": "published", "publication": "Macromolecules", "volume": "43", "number": "19", "publisher": "American Chemical Society", "pagerange": "8282-8289", "id_number": "CaltechAUTHORS:20101028-094727435", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101028-094727435", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-0966662" }, { "agency": "NSF", "grant_number": "CBET-0965812" }, { "agency": "NSF", "grant_number": "CBET-0966632" }, { "agency": "Department of Energy (DOE)" }, { "agency": "NSF Graduate Research Fellowship" } ] }, "doi": "10.1021/ma1013786", "resource_type": "article", "pub_year": "2010", "author_list": "Wanakule, Nisita S.; Virgili, Justin M.; et el." }, { "id": "https://authors.library.caltech.edu/records/szppz-ha594", "eprint_id": 19838, "eprint_status": "archive", "datestamp": "2023-08-22 00:35:33", "lastmod": "2023-10-20 21:57:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Yang-Yong-Biao", "name": { "family": "Yang", "given": "Yong-Biao" } }, { "id": "Sun-Zhao-Yan", "name": { "family": "Sun", "given": "Zhao-Yan" } }, { "id": "Fu-Cui-Liu", "name": { "family": "Fu", "given": "Cui-Liu" } }, { "id": "An-Lijia", "name": { "family": "An", "given": "Li-Jia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Monte Carlo simulation of a single ring among linear chains: Structural and dynamic heterogeneity", "ispublished": "pub", "full_text_status": "public", "keywords": "bonds (chemical); molecular configurations; Monte Carlo methods; polymerisation; polymers; self-diffusion", "note": "\u00a9 2010 American Institute of Physics.\nReceived 23 November 2009; accepted 30 June 2010; published online 10 August 2010.\nThis work is supported by the National Natural Science\nFoundation of China (NSFC) (Grant Nos. 50873098,\n50930001, and 20734003) programs and the Fund for\nCreative Research Groups (Grant No. 50921062). L.J.A. and\nZ.G.W. acknowledge the financial support of NSFC\n(Grant No. 20620120105). Z.Y.S. acknowledges the financial\nsupport of JLSTP (Grant No. 20070113).\n\nPublished - Yang2010p11278J_Chem_Phys.pdf
", "abstract": "We perform lattice Monte Carlo simulation using the bond-fluctuation model to examine the conformation and dynamic properties of a single small flexible ring polymer in the matrix of linear chains as functions of the degree of polymerization of the linear chains. The average conformation properties as gauged by the mean-square radius of gyration and asphericity parameter are insensitive to the chain length for all the chain lengths examined (30, 100, 300, and 1000). However, in the longer chain (300 and 1000) samples, there is an increased spread in the distribution of the value of these quantities, suggesting structural heterogeneity. The center-of-mass diffusion of the ring shows a rapid decrease with increasing chain length followed by a more gradual change for the two longer chain systems. In these longer chain systems, a wide spread in the value of the apparent self-diffusion coefficient is also observed, as well as qualitatively different square displacement trajectories among the different samples, suggesting heterogeneity in the dynamics. A primitive path analysis reveals that in these long chain systems, the ring can exist in topologically distinct states with respect to threading by the linear chains. Threading by the linear chain can dramatically slow down and in some cases stall the diffusive motion of the ring. We argue that the life times for these topological conformers can be longer than the disentanglement time of the linear chain matrix, so that the ring exhibits nonergodic behavior on time scales less or comparable to the life time of these conformers. Our results suggest a picture of the ring diffusion as one where the diffusion path consists of distinctive segments, each corresponding to a different conformer, with slow interconversion between the different conformers.", "date": "2010-08-14", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "133", "number": "6", "publisher": "American Institute of Physics", "pagerange": "Art. No. 064901", "id_number": "CaltechAUTHORS:20100908-152606750", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100908-152606750", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "50873098" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "50930001" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "20734003" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "20620120105" }, { "agency": "Fund for Creative Research Groups", "grant_number": "50921062" }, { "agency": "JLSTP", "grant_number": "20070113" } ] }, "doi": "10.1063/1.3466921", "primary_object": { "basename": "Yang2010p11278J_Chem_Phys.pdf", "url": "https://authors.library.caltech.edu/records/szppz-ha594/files/Yang2010p11278J_Chem_Phys.pdf" }, "resource_type": "article", "pub_year": "2010", "author_list": "Yang, Yong-Biao; Sun, Zhao-Yan; et el." }, { "id": "https://authors.library.caltech.edu/records/7jt25-er088", "eprint_id": 18882, "eprint_status": "archive", "datestamp": "2023-08-19 02:52:42", "lastmod": "2023-10-20 19:09:28", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lu-Yuyuan", "name": { "family": "Lu", "given": "Yuyuan" }, "orcid": "0000-0002-4073-678X" }, { "id": "Shi-Tongfei", "name": { "family": "Shi", "given": "Tongfei" } }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "Jin-Liping", "name": { "family": "Jin", "given": "Liping" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "A simple model for the anomalous intrinsic viscosity of dendrimers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2010 The Royal Society of Chemistry.\n\nReceived 5th March 2010, Accepted 28th April 2010.\nFirst published as an Advance Article on the web 14th May 2010.\n\nThis work was supported by the National Natural Science Foundation\nof China (NSFC) (No. 20734003) and the Fund for Creative\nResearch Groups (No. 50921062), further subsidized by the Special\nFunds for National Basic Research Program of China\n(No. 2009CB930100). T. F. S. thanks the support from NSFC\n(No. 20774096). L. P. J. thanks the support from NSFC\n(No. 10573007 and No. 10873006).\n\nPublished - Lu2010p10524Soft_Matter.pdf
", "abstract": "The intrinsic viscosity of dendrimers in solution shows several anomalous behaviors that have hitherto not been explained within the existing theoretical frameworks of either Zimm or Rouse. Here we propose a simple two-zone model based on the radial segmental density profile of the dendrimers and combine a non-draining core with a free-draining outer region description, to arrive at a simple formula that captures most of the main features in the intrinsic viscosity data obtained in experiments.", "date": "2010-06-21", "date_type": "published", "publication": "Soft Matter", "volume": "6", "number": "12", "publisher": "Royal Society of Chemistry", "pagerange": "2619-2622", "id_number": "CaltechAUTHORS:20100630-143040341", "issn": "1744-6848", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100630-143040341", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "20734003" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "20774096" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "10573007" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "10873006" }, { "agency": "Fund for Creative Research Groups", "grant_number": "50921062" }, { "agency": "Special Funds for National Basic Research Program of China", "grant_number": "2009CB930100" } ] }, "doi": "10.1039/c0sm00061b", "primary_object": { "basename": "Lu2010p10524Soft_Matter.pdf", "url": "https://authors.library.caltech.edu/records/7jt25-er088/files/Lu2010p10524Soft_Matter.pdf" }, "resource_type": "article", "pub_year": "2010", "author_list": "Lu, Yuyuan; Shi, Tongfei; et el." }, { "id": "https://authors.library.caltech.edu/records/epg8w-pqs13", "eprint_id": 17630, "eprint_status": "archive", "datestamp": "2023-08-19 01:42:03", "lastmod": "2023-10-20 00:05:14", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Jiafang", "name": { "family": "Wang", "given": "Jiafang" } }, { "id": "Guo-Kunkun", "name": { "family": "Guo", "given": "Kunkun" } }, { "id": "An-Lijia", "name": { "family": "An", "given": "Lijia" } }, { "id": "M\u00fcller-M", "name": { "family": "M\u00fcller", "given": "Marcus" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Micelles of Coil\u2212Comb Block Copolymers in Selective Solvents: Competition of Length Scales", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2010 American Chemical Society.\n\nReceived September 4, 2009; Revised Manuscript Received January 7, 2010.\nPublication Date (Web): January 25, 2010.\n\nWe thank Dr. Li Li for drawing our\nattention to their experimental results and for helpful discussions.\nFinancial support by the DFG within the Materials World Network\n(Mu 1674/4) and the National Natural Science Foundation\nof China (20620120105) is gratefully acknowledged. While this\nmanuscript was under review, the leading author of this article,\nDr. Jiafang Wang, passed away unexpectedly of some previously\nunknown health condition. We (K.K.G., L.J.A., M.M., and\nZ.G.W.) express our deepest sorrow at the loss of a dear colleague and friend.", "abstract": "We study micelles formed by the coil\u2212comb block copolymer, A-b-(A-g-B), in a B-selective solvent, S. The equilibrium distribution of micelles is obtained according to the thermodynamics of noninteracting micellar solutions, with the free energy of a single isolated micelle calculated using the self-consistent-field theory. Depending on the lengths of the various blocks and the balance of interactions, two types of micelles of different sizes and structures can be observed. This is a manifestation of the competition between two micellar assemblies of the coil\u2212comb block copolymer at different length scales.", "date": "2010-02-23", "date_type": "published", "publication": "Macromolecules", "volume": "43", "number": "4", "publisher": "American Chemical Society", "pagerange": "2037-2041", "id_number": "CaltechAUTHORS:20100302-131414201", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100302-131414201", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Deutsche Forschungsgemeinschaft (DFG)", "grant_number": "Mu 1674/4" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "20620120105" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/ma901977h", "resource_type": "article", "pub_year": "2010", "author_list": "Wang, Jiafang; Guo, Kunkun; et el." }, { "id": "https://authors.library.caltech.edu/records/bbzbz-r1348", "eprint_id": 17794, "eprint_status": "archive", "datestamp": "2023-08-19 01:32:58", "lastmod": "2023-10-20 00:14:07", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Fluctuation in electrolyte solutions: The self energy", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2010 The American Physical Society.\n\nReceived 12 August 2009; published 9 February 2010.\n\nPublished - Wang2010p7290Phys_Rev_E.pdf
", "abstract": "We address the issue of the self energy of the mobile ions in electrolyte solutions within a general Gaussian renormalized fluctuation theory using a field-theoretic approach. We introduce the Born radii of the ions in the form of a charge distribution allowing for different Born radii between the cations and anions. The model thus automatically yields a theory free of divergences and accounts for the solvation of the ions at the level of continuous dielectric media. In an inhomogeneous dielectric medium, the self energy is in general position dependent and differences in the self energy between cations and anions can give rise to local charge separation in a macroscopically neutral system. Treating the Born radius a as a smallness parameter, we show that the self energy can be split into an O(a^(\u22121)) nonuniversal contribution and an O(a^0) universal contribution that depends only on the ion concentration, valency, and the spatially varying dielectric constant. For a weakly inhomogeneous dielectric medium, the nonuniversal part of the self energy is shown to have the form of the Born energy with the local dielectric constant. This self energy is incorporated into the Poisson-Boltzmann equation as a simple means of including this local fluctuation effect in a mean-field theory. We illustrate the phenomenon of charge separation by considering cations and anions of difference sizes and valencies in a periodic dielectric medium.", "date": "2010-02", "date_type": "published", "publication": "Physical Review E", "volume": "81", "number": "2", "publisher": "American Physical Society", "pagerange": "021501", "id_number": "CaltechAUTHORS:20100324-111453101", "issn": "1539-3755", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100324-111453101", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "collection": "CaltechAUTHORS", "doi": "10.1103/PhysRevE.81.021501", "primary_object": { "basename": "Wang2010p7290Phys_Rev_E.pdf", "url": "https://authors.library.caltech.edu/records/bbzbz-r1348/files/Wang2010p7290Phys_Rev_E.pdf" }, "resource_type": "article", "pub_year": "2010", "author_list": "Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/z16wv-1wt54", "eprint_id": 15586, "eprint_status": "archive", "datestamp": "2023-08-20 01:31:01", "lastmod": "2023-10-19 14:36:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Jiang-Tao", "name": { "family": "Jiang", "given": "Tao" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Wu-Jianzhong", "name": { "family": "Wu", "given": "Jianzhong" }, "orcid": "0000-0002-4582-5941" } ] }, "title": "Electrostatic Regulation of Genome Packaging in Human Hepatitis B Virus", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2009 Biophysical Society Published by Elsevier Inc. Submitted August 28, 2008, and accepted for publication January 8, 2009. The authors are grateful to Dr. Jianming Hu for insightful comments on the\nbiological aspects of HBV. For financial support and computer time allocations,\nwe are grateful to the U.S. Department of Energy (DE-FG02-\n06ER46296) and to the National Energy Research Scientific Computing\nCenter (NERSC), which is supported by the Office of Science of the U.S.\nDepartment of Energy under contract No. DE-AC03-76SF0009.", "abstract": "Hepatitis B virus (HBV) is a contagious human pathogen causing liver diseases such as cirrhosis and hepatocellular\ncarcinoma. An essential step during HBV replication is packaging of a pregenomic (pg) RNA within the capsid of core antigens\n(HBcAgs) that each contains a flexible C-terminal tail rich in arginine residues. Mutagenesis experiments suggest that\npgRNA encapsidation hinges on its strong electrostatic interaction with oppositely charged C-terminal tails of the HBcAgs,\nand that the net charge of the capsid and C-terminal tails determines the genome size and nucleocapsid stability. Here, we elucidate\nthe biophysical basis for electrostatic regulation of pgRNA packaging in HBV by using a coarse-grained molecular model\nthat explicitly accounts for all nonspecific interactions among key components within the nucleocapsid. We find that for mutants\nwith variant C-terminal length, an optimal genome size minimizes an appropriately defined thermodynamic free energy. The thermodynamic\ndriving force of RNA packaging arises from a combination of electrostatic interactions and molecular excluded volume\neffects. The theoretical predictions of the RNA length and nucleocapsid internal structure are in good agreement with\navailable experiments for the wild-type HBV and mutants with truncated HBcAg C-termini.", "date": "2009-04-22", "date_type": "published", "publication": "Biophysical Journal", "volume": "96", "number": "8", "publisher": "Biophysical Society", "pagerange": "3065-3073", "id_number": "CaltechAUTHORS:20090903-143638577", "issn": "0006-3495", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090903-143638577", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Department of Energy (DOE)", "grant_number": "DE-FG02-06ER46296" }, { "agency": "National Energy Research Scientific Computing" }, { "agency": "Department of Energy (DOE)", "grant_number": "DE-AC03-76SF00098" } ] }, "doi": "10.1016/j.bpj.2009.01.009", "resource_type": "article", "pub_year": "2009", "author_list": "Jiang, Tao; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/2zvwb-ccb38", "eprint_id": 14766, "eprint_status": "archive", "datestamp": "2023-08-21 21:16:14", "lastmod": "2023-10-18 19:52:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Jiafang", "name": { "family": "Wang", "given": "Jiafang" } }, { "id": "M\u00fcller-M", "name": { "family": "M\u00fcller", "given": "Marcus" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nucleation in A/B/AB blends: Interplay between microphase assembly and macrophase separation", "ispublished": "pub", "full_text_status": "public", "keywords": "colloids; drops; emulsions; free energy; nucleation; phase separation; polymer blends", "note": "\u00a9 2009 American Institute of Physics.\nReceived 19 January 2009; accepted 24 February 2009; published 20 April 2009.\nFinancial support by the DFG within the Materials\nWorld Network Grant No. Mu 1674/4 is gratefully acknowledged.\nThis work is also partially supported by the\nNational Natural Science Foundation of China (Grant No.\n20620120105) Programs.\n\nPublished - Wang2009p2404J_Chem_Phys.pdf
", "abstract": "We study the interplay between microphase assembly and macrophase separation in A/B/AB ternary polymer blends by examining the free energy of localized fluctuation structures (micelles or droplets), with emphasis on the thermodynamic relationship between swollen micelles (microemulsion) and the macrophase-separated state, using self-consistent field theory and an extended capillary model. Upon introducing homopolymer B into a micelle-forming binary polymer blend A/AB, micelles can be swollen by B. A small amount of component B (below the A-rich binodal of macrophase coexistence) will not affect the stability of the swollen micelles. A large excess of homopolymer, B, will induce a microemulsion failure and lead to a macrophase separation. Between the binodal and the microemulsion failure concentration, macrophase separation in A/B/AB occurs by a two-step nucleation mechanism via a metastable microemulsion droplet of finite size. Our results illustrate a recently proposed argument that the two-step nucleation via a metastable intermediate is a general phenomenon in systems involving short-range attraction and long-range repulsion.", "date": "2009-04-21", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "130", "number": "15", "publisher": "American Institute of Physics", "pagerange": "154902", "id_number": "CaltechAUTHORS:20090803-100239123", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090803-100239123", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Deutsche Forschungsgemeinschaft (DFG)", "grant_number": "Mu 1674/4" }, { "agency": "National Natural Science Foundation of China (NSFC)", "grant_number": "20620120105" } ] }, "doi": "10.1063/1.3105340", "primary_object": { "basename": "Wang2009p2404J_Chem_Phys.pdf", "url": "https://authors.library.caltech.edu/records/2zvwb-ccb38/files/Wang2009p2404J_Chem_Phys.pdf" }, "resource_type": "article", "pub_year": "2009", "author_list": "Wang, Jiafang; M\u00fcller, Marcus; et el." }, { "id": "https://authors.library.caltech.edu/records/st3tt-qxr93", "eprint_id": 14452, "eprint_status": "archive", "datestamp": "2023-08-20 01:26:26", "lastmod": "2023-10-18 18:00:31", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Ting-Christina-L", "name": { "family": "Ting", "given": "Christina L." } }, { "id": "Makarov-D-E", "name": { "family": "Makarov", "given": "Dmitrii E." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "A Kinetic Model for the Enzymatic Action of Cellulase", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2009 American Chemical Society.\nReceived: December 3, 2008; Revised Manuscript Received: January 30, 2009. Publication Date (Web): March 17, 2009. \n\nWe thank Bradley Olsen, Frances Arnold, and Pete Heinzelman for helpful discussions. C.L.T. is thankful for financial support from an NIH training grant. D.E.M. acknowledges financial support from the Robert A. Welch Foundation (Grant F-1514) and the National Science Foundation (Grant CHE 0347862).", "abstract": "We develop a mechanochemical model for the dynamics of cellulase, a two-domain enzyme connected by a peptide linker, as it extracts and hydrolyzes a cellulose polymer from a crystalline substrate. We consider two random walkers, representing the catalytic domain (CD) and the carbohydrate binding module (CBM), whose rates for stepping are biased by the coupling through the linker and the energy required to lift the cellulose polymer from the crystalline surface. Our results show that the linker length and stiffness play a critical role in the cooperative action of the CD and CBM domains and that, for a given linker length, the steady-state hydrolysis shows a maximum at some intermediate linker stiffness. The maximum hydrolysis rate corresponds to a transition of the linker from a compressed to an extended conformation, where the system exhibits maximum fluctuation, as measured by the variance of the separation distance between the two domains and the dispersion around the mean hydrolysis speed. In the range of experimentally known values of the parameters of our model, improving the intrinsic hydrolytic activity of the CD leads to a proportional increase in the overall hydrolysis rate.", "date": "2009-04-09", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "113", "number": "14", "publisher": "American Chemical Society", "pagerange": "4970-4977", "id_number": "CaltechAUTHORS:20090629-095421715", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090629-095421715", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Robert A. Welch Foundation", "grant_number": "F-1514" }, { "agency": "NSF", "grant_number": "CHE 0347862" } ] }, "doi": "10.1021/jp810625k", "resource_type": "article", "pub_year": "2009", "author_list": "Ting, Christina L.; Makarov, Dmitrii E.; et el." }, { "id": "https://authors.library.caltech.edu/records/34ca2-1yt76", "eprint_id": 12922, "eprint_status": "archive", "datestamp": "2023-08-20 00:13:33", "lastmod": "2023-10-17 21:38:22", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Effects of Ion Solvation on the Miscibility of Binary Polymer Blends", "ispublished": "pub", "full_text_status": "restricted", "note": "Copyright \u00a9 2008 American Chemical Society. \n\nReceived: August 2, 2008; Revised Manuscript Received: September 23, 2008. Publication Date (Web): November 14, 2008. \n\nThe author thanks Nitash Balsara, Alexander Grosberg, Michael Rubinstein, and Ralph Colby for helpful discussions. \n\nThis article is part of the B: Karl Freed Festschrift special issue. http://pubs.acs.org/toc/jpcbfk/112/50", "abstract": "We study the effects of adding salt ions on the miscibility of a binary blend of polymers having different dielectric constants. The competition between the preference of the ions to be solvated by the component of the higher dielectric constant and the entropic tendency for the ions to be distributed uniformly results in nontrivial effects on the miscibility. We first study the thermodynamics of the polymer blend\u2212ion mixture using a simple Born model in a uniform dielectric medium of the average composition of the polymer blend. We then study the effect of local enrichment of the higher dielectric constant polymer near the ion. We find that when the dielectric constants of the polymers are both low, adding salt decreases the miscibility, while when the dielectric constants of the polymers are both high, the addition of salt enhances the miscibility. When the blend consists of a high dielectric constant polymer and a low dielectric constant polymer, miscibility is decreased if the low dielectric constant component is the majority and is increased if the high dielectric constant component is the majority. The effect becomes significant at ion concentrations corresponding to an order of one ion per polymer chain. The quantitative change in the effective \u03c7 parameter depends on the functional form of the composition dependence of the dielectric constant of the mixture. We also illustrate the difference between fixed ion concentration and fixed chemical potential of the ions.", "date": "2008-12-18", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "112", "number": "50", "publisher": "American Chemical Society", "pagerange": "16205-16213", "id_number": "CaltechAUTHORS:WANjpcb08", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WANjpcb08", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1021/jp806897t", "resource_type": "article", "pub_year": "2008", "author_list": "Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/w37pq-tbv47", "eprint_id": 11934, "eprint_status": "archive", "datestamp": "2023-08-22 13:18:55", "lastmod": "2023-10-17 15:59:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Li-Zi-Qi", "name": { "family": "Li", "given": "Zi-Qi" } }, { "id": "Sun-Zhao-Yan", "name": { "family": "Sun", "given": "Zhao-Yan" } }, { "id": "An-Lijia", "name": { "family": "An", "given": "Li-Jia" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Heterogeneity in structurally arrested hard spheres", "ispublished": "pub", "full_text_status": "public", "keywords": "disordered solids; structure of simple liquids; theory and modeling of the glass transition", "note": "Copyright \u00a9 Institute of Physics and IOP Publishing Limited 2008. \n\nReceived 17 July 2008, accepted for publication 9 September 2008. Published 8 October 2008. Print publication: Issue 2 (October 2008). \n\nThis work is supported by the National Natural Science Foundation of China (20574070, 20734003, 20620120105) Programs and the Fund for Creative Research Groups (50621302). ZYS also acknowledges the financial support of JLSTP (20070113).\n\nPublished - LIZepl08.pdf
Supplemental Material - LIZepl08supp.pdf
", "abstract": "When cooled or compressed sufficiently rapidly, a liquid vitrifies into a glassy amorphous state. Vitrification in a dense liquid is associated with jamming of the particles. For hard spheres, the density and degree of order in the final structure depend on the compression rate: simple intuition suggests, and previous computer simulation demonstrates, that slower compression results in states that are both denser and more ordered. In this work, we use the Lubachevsky-Stillinger algorithm to generate a sequence of structurally arrested hard-sphere states by varying the compression rate. We find that while the degree of order, as measured by both bond-orientation and translation order parameters, increases monotonically with decreasing compression rate, the density of the arrested state first increases, then decreases, then increases again, as the compression rate decreases, showing a minimum at an intermediate compression rate. Examination of the distribution of the local order parameters and the distribution of the root-mean-square fluctuation of the particle positions, as well as direct visual inspection of the arrested structures, reveal that they are structurally heterogeneous, consisting of disordered, amorphous regions and locally ordered crystal-like domains. In particular, the low-density arrested states correspond with many interconnected small crystal clusters that form a polycrystalline network interspersed in an amorphous background, suggesting that jamming by the domains may be an important mechanism for these states.", "date": "2008-10-08", "date_type": "published", "publication": "Europhysics Letters", "volume": "84", "number": "2", "publisher": "IOP", "pagerange": "Art. No. 26005", "id_number": "CaltechAUTHORS:LIZepl08", "issn": "0295-5075", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:LIZepl08", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Natural Science Foundation of China", "grant_number": "20574070" }, { "agency": "National Natural Science Foundation of China", "grant_number": "20734003" }, { "agency": "National Natural Science Foundation of China", "grant_number": "20620120105" }, { "agency": "Fund for Creative Research Groups", "grant_number": "50621302" }, { "agency": "JLSTP", "grant_number": "20070113" } ] }, "doi": "10.1209/0295-5075/84/26005", "primary_object": { "basename": "LIZepl08.pdf", "url": "https://authors.library.caltech.edu/records/w37pq-tbv47/files/LIZepl08.pdf" }, "related_objects": [ { "basename": "LIZepl08supp.pdf", "url": "https://authors.library.caltech.edu/records/w37pq-tbv47/files/LIZepl08supp.pdf" } ], "resource_type": "article", "pub_year": "2008", "author_list": "Li, Zi-Qi; Sun, Zhao-Yan; et el." }, { "id": "https://authors.library.caltech.edu/records/5ncab-yvb12", "eprint_id": 9612, "eprint_status": "archive", "datestamp": "2023-08-22 11:03:32", "lastmod": "2023-10-16 22:23:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Cheng-Zhong", "name": { "family": "Zhang", "given": "Cheng-Zhong" }, "orcid": "0000-0001-8825-7158" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nucleation of membrane adhesions", "ispublished": "pub", "full_text_status": "public", "keywords": "adhesion; biomechanics; biomembranes; biomimetics; cellular biophysics; free energy; molecular biophysics; nucleation; proteins", "note": "\u00a9 2008 The American Physical Society. \n\n(Received 15 September 2007; revised 11 December 2007; published 11 February 2008) \n\nThis work is supported by the National Science Foundation through MRSEC-Caltech.\n\nPublished - ZHApre08.pdf
", "abstract": "Recent experimental and theoretical studies of biomimetic membrane adhesions [Bruinsma et al., Phys. Rev. E 61, 4253 (2000); Boulbitch et al., Biophys. J. 81, 2743 (2001)] suggested that adhesion mediated by receptor interactions is due to the interplay between membrane undulations and a double-well adhesion potential, and should be a first-order transition. We study the nucleation of membrane adhesion by finding the minimum-energy path on the free energy surface constructed from the bending free energy of the membrane and the double-well adhesion potential. We find a nucleation free energy barrier around 20kBT for adhesion of flexible membranes, which corresponds to fast nucleation kinetics with a time scale of the order of seconds. For cell membranes with a larger bending rigidity due to the actin network, the nucleation barrier is higher and may require active processes such as the reorganization of the cortex network to overcome this barrier. Our scaling analysis suggests that the geometry of the membrane shapes of the adhesion contact is controlled by the adhesion length that is determined by the membrane rigidity, the barrier height, and the length scale of the double-well potential, while the energetics of adhesion is determined by the depths of the adhesion potential. These results are verified by numerical calculations.", "date": "2008-02", "date_type": "published", "publication": "Physical Review E", "volume": "77", "number": "2", "publisher": "American Physical Society", "pagerange": "Art. No. 021906", "id_number": "CaltechAUTHORS:ZHApre08", "issn": "1539-3755", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:ZHApre08", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1103/PhysRevE.77.021906", "primary_object": { "basename": "ZHApre08.pdf", "url": "https://authors.library.caltech.edu/records/5ncab-yvb12/files/ZHApre08.pdf" }, "resource_type": "article", "pub_year": "2008", "author_list": "Zhang, Cheng-Zhong and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/eej9a-7tq35", "eprint_id": 79314, "eprint_status": "archive", "datestamp": "2023-08-19 21:40:21", "lastmod": "2023-10-26 14:47:54", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Cheng-Zhong", "name": { "family": "Zhang", "given": "Cheng-Zhong" }, "orcid": "0000-0001-8825-7158" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Polymer-Tethered Ligand-Receptor Interactions between Surfaces II", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 2007 American Chemical Society. \n\nReceived 19 June 2007. Published online 15 November 2007. Published in print 1 December 2007. \n\nThis work is supported by the National Science Foundation through MRSEC-CALTECH.\n\nSupplemental Material - la7017133-file005.pdf
", "abstract": "In this paper, we analyze the thermodynamics of interactions between surfaces mediated by polymer-tethered ligand-receptor binding. From statistical thermodynamics calculations, we obtain an effective two-dimensional binding constant reflecting contributions from the microscopic binding affinity as well as from the conformation entropy of the polymer tethers. The total interaction is a result of the interplay between attractive binding and repulsion due to confinement of the polymer chains. We illustrate the differences between three scenarios when the binding molecules are (1) immobile, (2) mobile with a fixed density, and (3) mobile with a fixed chemical potential (connected to a reservoir), which correspond to different biological or experimental situations. The key features of interactions, including the range of adhesion (onset of binding) and the equilibrium separation, can be obtained from scaling analysis and are verified by numerical solutions. In addition, we also extend our method of treating the quenched case with immobile ligands and receptors developed in a previous paper [Martin, J. I.; Zhang, C.-Z.; Wang, Z.-G. J. Polym. Sci., Part B: Polym. Phys. 2006, 44, 2621\u22122637] as a density expansion in terms of both ligand and receptor densities. Finally, we examine several cases having ligand-receptor pairs with different tether lengths and binding affinities, and/or nonbinding linear polymers as steric repellers. Such systems can exhibit complex interactions such as a double-well potential, or a bound state with an adjustable barrier (due to the repellers), which have both biological and bioengineering relevance.", "date": "2007-12-18", "date_type": "published", "publication": "Langmuir", "volume": "23", "number": "26", "publisher": "American Chemical Society", "pagerange": "13024-13039", "id_number": "CaltechAUTHORS:20170725-072342785", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170725-072342785", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1021/la7017133", "primary_object": { "basename": "la7017133-file005.pdf", "url": "https://authors.library.caltech.edu/records/eej9a-7tq35/files/la7017133-file005.pdf" }, "resource_type": "article", "pub_year": "2007", "author_list": "Zhang, Cheng-Zhong and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/1g4bj-7f942", "eprint_id": 8639, "eprint_status": "archive", "datestamp": "2023-08-22 09:48:44", "lastmod": "2023-10-16 21:36:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Hutchens-S-B", "name": { "family": "Hutchens", "given": "Shelby B." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Metastable cluster intermediates in the condensation of charged macromolecule solutions", "ispublished": "pub", "full_text_status": "public", "keywords": "Boltzmann equation; capillarity; condensation; macromolecules; phase separation; Poisson equation", "note": "\u00a92007 American Institute of Physics \n\n(Received 4 June 2007; accepted 26 June 2007; published online 31 August 2007) \n\nOne of the authors (S.B.H.) would like to thank Betty and Gordon Moore for the teaching and research fellowship.\n\nPublished - HUTjcp07.pdf
", "abstract": "The authors examine the possibility of a two-step nucleation to the bulk condensation transition that proceeds via a metastable liquid cluster intermediate having some preferred size. The metastable intermediate is stabilized by electrostatic repulsion, which becomes screened by small mobile ions at sufficiently large cluster sizes, thus allowing the eventual condensation to a bulk phase. Our calculation employs a capillary model for the cluster and the electrostatic interactions are treated using the Poisson-Boltzmann approach. Condensation via this metastable intermediate may be a very general phenomenon which applies not only to solutions of charged particles (e.g., proteins, colloidal particles, and polyelectrolytes) but to any system involving short-range attraction and long-range repulsion undergoing macrophase separation in which a metastable microphase separation is also possible.", "date": "2007-08-28", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "127", "number": "8", "publisher": "American Institute of Physics", "pagerange": "Art. No. 084912", "id_number": "CaltechAUTHORS:HUTjcp07", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:HUTjcp07", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Gordon and Betty Moore Foundation" } ] }, "doi": "10.1063/1.2761891", "primary_object": { "basename": "HUTjcp07.pdf", "url": "https://authors.library.caltech.edu/records/1g4bj-7f942/files/HUTjcp07.pdf" }, "resource_type": "article", "pub_year": "2007", "author_list": "Hutchens, Shelby B. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/shvav-0vf80", "eprint_id": 76810, "eprint_status": "archive", "datestamp": "2023-08-19 18:24:19", "lastmod": "2023-10-25 16:53:13", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Area Expansion and Adsorption Isotherm in Protein Binding to Mixed Lipid Membranes", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2006 American Chemical Society. \n\nReceived 11 October 2005. Date accepted 23 January 2006. Published online 11 April 2006. Published in print 1 August 2006. \n\nThe author wishes to thank Dan Pack and Frances Arnold for discussions, which led to this work.", "abstract": "We present a thermodynamic analysis of protein adsorption to a mixed lipid monolayer containing a binding component and a nonbinding component at constant surface pressure. We derive the general equations for the adsorption isotherm and for the area expansion of the monolayer. In the limits of either low or high surface coverage, simplified forms of these equations are obtained. We construct simple thermodynamic models to examine the crossover from low to high surface coverage.", "date": "2006-08-02", "date_type": "published", "publication": "Industrial & Engineering Chemistry Research", "volume": "45", "number": "16", "publisher": "American Chemical Society", "pagerange": "5538-5547", "id_number": "CaltechAUTHORS:20170421-092507037", "issn": "0888-5885", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170421-092507037", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1021/ie051136e", "resource_type": "article", "pub_year": "2006", "author_list": "Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/x89wv-vc013", "eprint_id": 79293, "eprint_status": "archive", "datestamp": "2023-08-19 18:04:30", "lastmod": "2023-10-26 14:46:33", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Cho-Junhan", "name": { "family": "Cho", "given": "Junhan" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "A Simple Field-Theoretic Simulation Method for Compressible Block Copolymer Systems", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2006 American Chemical Society. \n\nReceived 1 December 2005. Published online 27 May 2006. Published in print 1 June 2006. \n\nThis work was supported by the Korea Research Foundation Grant (KRF-2005-013-D00020). J.C. acknowledges Dr. Y. Bohbot-Raviv for sharing the code for incompressible block copolymer systems.", "abstract": "A simple field-theoretic simulation method based on a compressible random-phase approximation (RPA) theory has been suggested to understand the self-assembly behavior and its pressure responses of compressible block copolymer systems. Finite compressibility is incorporated in the free energy functional for the dissipative dynamics through effective RPA interactions that account for the excluded volume and the attractive nonbonded interactions. It was shown that basic equation-of-state parameters completely characterizing given block components readily yield stable and metastable morphologies without any presumed symmetry over a wide range of temperature\u2212pressure\u2212composition space for copolymer melts in unconfined or confined geometry. It was demonstrated that the simulation tool is capable of predicting in a unified way block copolymer phase behavior, not only exhibiting nanoscale ordering either upon cooling or reversely upon heating, but also revealing barotropicity and baroplasticity.", "date": "2006-06-27", "date_type": "published", "publication": "Macromolecules", "volume": "39", "number": "13", "publisher": "American Chemical Society", "pagerange": "4576-4584", "id_number": "CaltechAUTHORS:20170724-095313046", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-095313046", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Korea Research Fountdation", "grant_number": "KRF-2005-013-D00020" } ] }, "doi": "10.1021/ma052565r", "resource_type": "article", "pub_year": "2006", "author_list": "Cho, Junhan and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/wwvfw-xk407", "eprint_id": 77967, "eprint_status": "archive", "datestamp": "2023-08-19 17:35:26", "lastmod": "2023-10-25 23:36:58", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Witman-J-E", "name": { "family": "Witman", "given": "Jennifer E." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "A Lattice Model of Vitrification and Gelation", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2006 American Chemical Society. \n\nReceived 15 March 2005. Published online 4 March 2006. Published in print 1 March 2006. \n\nThis research was supported in part by the National Science Foundation through the Center for the Science and Engineering of Materials.", "abstract": "In this work we introduce a simple lattice model with T-shaped molecules in two dimensions that exhibits a rich range of morphological behaviors. Depending on the volume fraction and quench path, this system can adopt uniform liquid, solution, and phase-separated states, as well as inhomogeneous glass or gel-like states, as revealed by dynamic mean-field simulations. An important characteristic of this system is the existence of a large number of degenerate low-energy states with small barriers that leads to a broad, kinetically explored landscape. The mean-field stability and phase diagram of this model is constructed and provides a useful guide for understanding the complex behaviors of the system. One striking feature is that there is a cascade of instabilities that converge to mark the onset of what we identify as the glass transition. Both dynamic mean-field and Monte Carlo simulations reveal glass-like relaxation dynamics. Our results lead to a picture of gelation as a continuation of the glass transition into the two-phase region, or equivalently, as an incomplete phase separation arrested by the onset of the glass transition.", "date": "2006-03-30", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "110", "number": "12", "publisher": "American Chemical Society", "pagerange": "6312-6324", "id_number": "CaltechAUTHORS:20170606-105748587", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170606-105748587", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1021/jp051365e", "resource_type": "article", "pub_year": "2006", "author_list": "Witman, Jennifer E. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/1m91w-x3533", "eprint_id": 3803, "eprint_status": "archive", "datestamp": "2023-08-22 05:12:51", "lastmod": "2023-10-16 16:10:06", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Zhang-Cheng-Zhong", "name": { "family": "Zhang", "given": "Cheng-Zhong" }, "orcid": "0000-0001-8825-7158" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Random isotropic structures and possible glass transitions in diblock copolymer melts", "ispublished": "pub", "full_text_status": "public", "keywords": "polymer melts; polymer blends; random processes; glass transition; polymerisation; vitrification; phase separation; order-disorder transformations; fluctuations; vitreous state", "note": "\u00a9 2006 The American Physical Society \n\n(Received 16 March 2005; published 15 March 2006) \n\nThis work was supported by the National Science Foundation through the Center for the Science and Engineering of Materials at Caltech.\n\nPublished - ZHApre06.pdf
", "abstract": "We study the microstructural glass transition in diblock-copolymer melts using a thermodynamic replica approach. Our approach performs an expansion in terms of the natural smallness parameter\u2014the inverse of the scaled degree of polymerization [overline N]\u2014which allows us to systematically study the approach to mean-field behavior as the degree of polymerization increases. We find that in the limit of infinite chain length, both the onset of glassiness and the vitrification transition (Kauzmann temperature) collapse to the mean-field spinodal, suggesting that the spinodal can be regarded as the mean-field signature for glass transitions in this class of microphase-separating system. We also study the order-disorder transition (ODT) within the same theoretical framework; in particular, we include the leading-order fluctuation corrections due to the cubic interaction in the coarse-grained Hamiltonian, which has been ignored in previous studies of the ODT in block copolymers. We find that the cubic term stabilizes both the ordered (body-centered-cubic) phase and the glassy state relative to the disordered phase. In melts of symmetric copolymers the glass transition always occurs after the order-disorder transition (below the ODT temperature), but for asymmetric copolymers, it is possible for the glass transition to precede the ordering transition.", "date": "2006-03", "date_type": "published", "publication": "Physical Review E", "volume": "73", "number": "3", "publisher": "American Physical Society", "pagerange": "Art. No. 031804", "id_number": "CaltechAUTHORS:ZHApre06", "issn": "1539-3755", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:ZHApre06", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1103/PhysRevE.73.031804", "primary_object": { "basename": "ZHApre06.pdf", "url": "https://authors.library.caltech.edu/records/1m91w-x3533/files/ZHApre06.pdf" }, "resource_type": "article", "pub_year": "2006", "author_list": "Zhang, Cheng-Zhong and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/3vxhb-cyy56", "eprint_id": 1367, "eprint_status": "archive", "datestamp": "2023-08-22 04:13:15", "lastmod": "2023-10-13 22:46:51", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Spakowitz-A-J", "name": { "family": "Spakowitz", "given": "Andrew J." }, "orcid": "0000-0002-0585-1942" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "End-to-end distance vector distribution with fixed end orientations for the wormlike chain model", "ispublished": "pub", "full_text_status": "public", "keywords": "macromolecules; polymers; molecular configurations; molecular orientation; Gaussian processes", "note": "\u00a92005 The American Physical Society \n\n(Received 5 February 2005; revised 16 June 2005; published 7 October 2005) \n\nThe authors gratefully acknowledge Lei Zhang and Niles Pierce for their involvement during the initial phase of this work which contributed to its development. The authors also thank Paul Wiggins and Phil Nelson for helpful discussions. This work was supported in part by the National Science Foundation (Grant No. DMR-9970589).\n\nPublished - SPApre05.pdf
", "abstract": "We find exact expressions for the end-to-end distance vector distribution function with fixed end orientations for the wormlike chain model. This function in Fourier-Laplace space adopts the form of infinite continued fractions, which emerges upon exploiting the hierarchical structure of the moment-based expansion. Our results are used to calculate the root-mean-square end displacement in a given direction for a chain with both end orientations fixed. We find that the crossover from rigid to flexible chains is marked by the root-mean-square end displacement slowly losing its angular dependence as the coupling between chain conformation and end orientation wanes. However, the coupling remains strong even for relatively flexible chains, suggesting that the end orientation strongly influences chain conformation for chains that are several persistence lengths long. We then show the behavior of the distribution function by a density plot of the probability as a function of the end-to-end distance vector for a wormlike chain in two dimensions with one end pointed in a fixed direction and the other end free (in its orientation). As we progress from high to low rigidity, the distribution function shifts from being peaked at a location near the full contour length of the chain in the forward direction, corresponding to a straight configuration, to being peaked near zero end separation, as in the Gaussian limit. The function exhibits double peaks in the crossover between these limiting behaviors.", "date": "2005-10", "date_type": "published", "publication": "Physical Review E", "volume": "72", "number": "4", "publisher": "American Physical Society", "pagerange": "Art. no. 041802", "id_number": "CaltechAUTHORS:SPApre05", "issn": "1539-3755", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:SPApre05", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Science Foundation", "grant_number": "DMR-9970589" } ] }, "doi": "10.1103/PhysRevE.72.041802", "primary_object": { "basename": "SPApre05.pdf", "url": "https://authors.library.caltech.edu/records/3vxhb-cyy56/files/SPApre05.pdf" }, "resource_type": "article", "pub_year": "2005", "author_list": "Spakowitz, Andrew J. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/ja7b6-0ym34", "eprint_id": 743, "eprint_status": "archive", "datestamp": "2023-08-22 03:58:22", "lastmod": "2023-10-13 21:57:08", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bois-J-S", "name": { "family": "Bois", "given": "Justin S." }, "orcid": "0000-0001-7137-8746" }, { "id": "Venkataraman-S", "name": { "family": "Venkataraman", "given": "Suvir" } }, { "id": "Choi-Harry-M-T", "name": { "family": "Choi", "given": "Harry M. T." }, "orcid": "0000-0002-1530-0773" }, { "id": "Spakowitz-A-J", "name": { "family": "Spakowitz", "given": "Andrew J." }, "orcid": "0000-0002-0585-1942" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Pierce-N-A", "name": { "family": "Pierce", "given": "Niles A." }, "orcid": "0000-0003-2367-4406" } ] }, "title": "Topological constraints in nucleic acid hybridization kinetics", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 The Author 2005. Published by Oxford University Press. The online version of this article has been published under an open access model. Users are entitled to use, reproduce, disseminate, or display the open access version of this article for non-commercial purposes provided that: the original authorship is properly and fully attributed; the Journal and Oxford University Press are attributed as the original place of publication with the correct citation details given; if an article is subsequently reproduced or disseminated not in its entirety but only in part or as a derivative work this must be clearly indicated. For commercial re-use, please contact journals.permissions@oupjournals.org \n\nReceived April 24, 2005. Revised May 17, 2005. Accepted July 4, 2005. \n\nWe are grateful to J. Bloom for performing the initial experimental studies on the kissing hairpin system, to G.Seelig for discussions on hybridization catalysts, and to H. Isambert for discussions on the disparity in chain diffusion and helix nucleation time scales. This work was supported by the Charles Lee Powell Foundation (N.A.P.), the Ralph M. Parsons Foundation (N.A.P.), the NSF CAREER program (N.A.P.) and the Caltech Center for Biological Circuit Design (S.V.). Funding to pay the Open Access publication charges for this article was provided by NSF grant CCF-0448835.\n\nConflict of interest statement. None declared.\n\nThe authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors.\n\nPublished - BOInar05.pdf
", "abstract": "A theoretical examination of kinetic mechanisms for forming knots and links in nucleic acid structures suggests that molecules involving base pairs between loops are likely to become topologically trapped in persistent frustrated states through the mechanism of 'helix-driven wrapping'. Augmentation of the state space to include both secondary structure and topology in describing the free energy landscape illustrates the potential for topological effects to influence the kinetics and function of nucleic acid strands. An experimental study of metastable complementary 'kissing hairpins' demonstrates that the topological constraint of zero linking number between the loops effectively prevents conversion to the minimum free energy helical state. Introduction of short catalyst strands that break the topological constraint causes rapid conversion to full duplex.", "date": "2005-08", "date_type": "published", "publication": "Nucleic Acids Research", "volume": "33", "number": "13", "publisher": "Oxford University Press", "pagerange": "4090-4095", "id_number": "CaltechAUTHORS:BOInar05", "issn": "0305-1048", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:BOInar05", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Charles Lee Powell Foundation" }, { "agency": "Ralph M. Parsons Foundation" }, { "agency": "Caltech Center for Biological Circuit Design" }, { "agency": "NSF", "grant_number": "CCF-0448835" } ] }, "doi": "10.1093/nar/gki721", "pmcid": "PMC1180668", "primary_object": { "basename": "BOInar05.pdf", "url": "https://authors.library.caltech.edu/records/ja7b6-0ym34/files/BOInar05.pdf" }, "resource_type": "article", "pub_year": "2005", "author_list": "Bois, Justin S.; Venkataraman, Suvir; et el." }, { "id": "https://authors.library.caltech.edu/records/t2gxq-ynt52", "eprint_id": 79280, "eprint_status": "archive", "datestamp": "2023-08-19 15:28:56", "lastmod": "2023-10-26 14:45:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Jiafang", "name": { "family": "Wang", "given": "Jiafang" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Yang-Yuliang", "name": { "family": "Yang", "given": "Yuliang" } } ] }, "title": "Nature of Disordered Micelles in Sphere-Forming Block Copolymer Melts", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2005 American Chemical Society. \n\nReceived 29 September 2004. Published online 10 February 2005. Published in print 1 March 2005. \n\nThis work is supported by the NSF of China, the Special Project for Fundamental Researches of the Ministry of Science and Technology, and the US NSF under Grant DMR-9957147. We are grateful to Dr. M. W. Matsen for generously providing us with the SCFT data of the free energy of the fcc and bcc phases and of the phase boundaries. J.F.W. thanks Dr. Hongdong Zhang and Dr. Feng Qiu for very helpful discussions.", "abstract": "Taking a nucleation perspective, we study the nature of the disordered micelles in highly asymmetric, sphere-forming diblock copolymer melts using the self-consistent-field theory. The micelles are shown to correspond to strong, activated, localized composition fluctuations in the disordered state due to finite molecular weights. By taking into account the translational entropy of the micelles, we obtain the concentration and the free energy of the disordered micelles. The critical micelle temperature (in terms of the familiar combination \u03c7N), operationally defined to correspond to the onset of sufficient number of micelles in the system, is identified by invoking a criterion involving the concentration of micelles. The disordered micelles are part of the disordered phase, and the only phase transition between the disordered state and the ordered phase is the order\u2212disorder transition (ODT). However, there exists a sharply defined temperature (higher than the critical micelle temperature), which we term the micelle dissociation temperature, beyond which micelles with finite lifetimes become impossible. The range of \u03c7N for the disordered micelles to be observable shrinks as N-1/2 with increasing degrees of polymerization N of the copolymers. In the infinite molecular weight limit, the window vanishes and the mean-field phase diagram calculated by Matsen and Bates is recovered. The disordered micelles, as a part of the disordered phase, contribute to the increased scattering intensity and the low-q shift of the structure factor in diblock copolymer melts near the ODT.", "date": "2005-03-08", "date_type": "published", "publication": "Macromolecules", "volume": "38", "number": "5", "publisher": "American Chemical Society", "pagerange": "1979-1988", "id_number": "CaltechAUTHORS:20170724-072208958", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170724-072208958", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Science Foundation of China" }, { "agency": "Ministry of Science and Technology (China)" }, { "agency": "NSF", "grant_number": "DMR-9957147" } ] }, "doi": "10.1021/ma047990j", "resource_type": "article", "pub_year": "2005", "author_list": "Wang, Jiafang; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/9m6mt-p7303", "eprint_id": 77004, "eprint_status": "archive", "datestamp": "2023-08-19 14:08:55", "lastmod": "2023-10-25 17:12:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bohbot-Raviv-Y", "name": { "family": "Bohbot-Raviv", "given": "Yardena" } }, { "id": "Snyder-T-M", "name": { "family": "Snyder", "given": "Thomas M." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Reversible Association of Telechelic Molecules: An Application of Graph Theory", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2004 American Chemical Society. \n\nReceived 12 January 2004. Published online 30 July 2004. Published in print 1 August 2004. \n\nWe thank Professor Avinoam Ben-Shaul and Professor Michael Rubinstein for helpful discussions. This research is supported in part by the National Science Foundation through the Center for the Science and Engineering of Materials. T.M.S. acknowledges financial support from the Caltech Summer Undergraduate Research Program.", "abstract": "We develop a method for calculating the exact free energy of tree clusters formed from associating telechelic molecules. The method uses the concept of rooted trees from the graph theory to enumerate all topologically distinct trees having a maximum degree of branching; it recursively separates the trees into different classes based on their connectivity, thus enabling the exact summation of the trees weighted by their respective Boltzmann factors. We apply our method to studying the pregel properties in pure telechelic solutions and in mixed telechelic and single-associating-end polymer solutions. We highlight the effect of energetic tendency for branching in the former and the effect of competitive association in the latter.", "date": "2004-08-31", "date_type": "published", "publication": "Langmuir", "volume": "20", "number": "18", "publisher": "American Chemical Society", "pagerange": "7860-7870", "id_number": "CaltechAUTHORS:20170427-110128717", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170427-110128717", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Caltech Summer Undergraduate Research Fellowship (SURF)" } ] }, "doi": "10.1021/la049906z", "resource_type": "article", "pub_year": "2004", "author_list": "Bohbot-Raviv, Yardena; Snyder, Thomas M.; et el." }, { "id": "https://authors.library.caltech.edu/records/4c25x-rdc14", "eprint_id": 76954, "eprint_status": "archive", "datestamp": "2023-08-19 13:58:55", "lastmod": "2023-10-25 17:01:39", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Spakowitz-A-J", "name": { "family": "Spakowitz", "given": "Andrew J." }, "orcid": "0000-0002-0585-1942" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Exact Results for a Semiflexible Polymer Chain in an Aligning Field", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2004 American Chemical Society. \n\nReceived January 5, 2004; Revised Manuscript Received April 23, 2004. Publication Date (Web): June 22, 2004. \n\nThis work was supported in part by the National Science Foundation (DMR-9970589).", "abstract": "We provide exact results for the Laplace-transformed partition function of a wormlike chain subject to a tensile force and in a nematic field, in both two and three dimensions. The results are in the form of infinite continued fractions, which are obtained by exploiting the hierarchical structure of a moment-based expansion of the partition function. The case of an imaginary force corresponds to the end-to-end distance distribution in Laplace\u2212Fourier space. We illustrate the utility of these exact results by examining the structure factor of a wormlike chain, the deformation free energy of a chain in a nematic field, and the self-consistent-field solution for the isotropic\u2212nematic transition of wormlike chains.", "date": "2004-07-27", "date_type": "published", "publication": "Macromolecules", "volume": "37", "number": "15", "publisher": "American Chemical Society", "pagerange": "5814-5823", "id_number": "CaltechAUTHORS:20170426-132616212", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170426-132616212", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1021/ma049958v", "resource_type": "article", "pub_year": "2004", "author_list": "Spakowitz, Andrew J. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/yy00v-d0n26", "eprint_id": 6761, "eprint_status": "archive", "datestamp": "2023-08-22 02:09:32", "lastmod": "2023-10-16 20:31:12", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Jiafang", "name": { "family": "Wang", "given": "Jiafang" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Yang-Yuliang", "name": { "family": "Yang", "given": "Yuliang" } } ] }, "title": "Nucleation in binary polymer blends: Effects of foreign mesoscopic spherical particles", "ispublished": "pub", "full_text_status": "public", "keywords": "DENSITY-FUNCTIONAL APPROACH; ION-INDUCED NUCLEATION; HETEROGENEOUS NUCLEATION; DIPOLAR FLUIDS; MIXTURES; INTERPLAY", "note": "\u00a92004 American Institute of Physics. \n\nReceived: 25 February 2004; accepted: 21 April 2004. \n\nFinancial support by the NSF of China and the Special Project for Fundamental Researches of the Ministry of Science and Technology are acknowledged. Z.G.W. acknowledges the support by the US National Science Foundation (Grant No. DMR-9970589). J.F.W. thanks Hongdong Zhang and Feng Qiu for very helpful discussions.\n\nPublished - WANJjcp04.pdf
", "abstract": "We study nucleation in binary polymer blends in the presence of mesoscopic spherical particles using self-consistent field theory, considering both heterogeneous and homogeneous nucleation mechanisms. Heterogeneous nucleation is found to be highly sensitive to surface selectivity and particle size, with rather subtle dependence on the particle size. Particles that preferentially adsorb the nucleating species generally favor heterogeneous nucleation. For sufficiently strong adsorption, barrierless nucleation is possible. By comparing the free energy barrier for homogeneous and heterogeneous nucleation, we construct a kinetic phase diagram.", "date": "2004-07-08", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "121", "number": "2", "publisher": "American Institute of Physics", "pagerange": "1105-1113", "id_number": "CaltechAUTHORS:WANJjcp04", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WANJjcp04", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Science Foundation of China" }, { "agency": "Special Project for Fundamental Researches, Ministry of Science and Technology" }, { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1063/1.1761053", "primary_object": { "basename": "WANJjcp04.pdf", "url": "https://authors.library.caltech.edu/records/yy00v-d0n26/files/WANJjcp04.pdf" }, "resource_type": "article", "pub_year": "2004", "author_list": "Wang, Jiafang; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/zeq7j-8gh67", "eprint_id": 27183, "eprint_status": "archive", "datestamp": "2023-08-22 02:06:53", "lastmod": "2023-10-24 16:56:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Endelman-J-B", "name": { "family": "Endelman", "given": "Jeffrey B." } }, { "id": "Silberg-J-J", "name": { "family": "Silberg", "given": "Jonathan J." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Arnold-F-H", "name": { "family": "Arnold", "given": "Frances H." }, "orcid": "0000-0002-4027-364X" } ] }, "title": "Site-directed protein recombination as a shortest-path problem", "ispublished": "pub", "full_text_status": "restricted", "keywords": "dynamic programming; laboratory evolution; optimization; protein design; recombination", "note": "\u00a9 2004 Oxford University Press. Received August 12, 2004.\nAccepted August 16, 2004. \nPublished online August 25, 2004.\nEdited by Stephen Mayo. We thank Costas Maranas, Matt DeLisa, Jeff Saven and Niles Pierce for their comments on the manuscript. This work was supported by National Institutes of Health Grant R01 GM068664-01, Army Research Office Contract DAAD19-03-D-0004, the W. M. Keck Foundation, a National Defense Science and Engineering Graduate Fellowship (J.B.E.) and NIH Fellowship F32 GM64949-01 (J.J.S.).", "abstract": "Protein function can be tuned using laboratory evolution, in which one rapidly searches through a library of proteins for the properties of interest. In site-directed recombination, n crossovers are chosen in an alignment of p parents to define a set of p(n + 1) peptide fragments. These fragments are then assembled combinatorially to create a library of p^(n+1) proteins. We have developed a computational algorithm to enrich these libraries in folded proteins while maintaining an appropriate level of diversity for evolution. For a given set of parents, our algorithm selects crossovers that minimize the average energy of the library, subject to constraints on the length of each fragment. This problem is equivalent to finding the shortest path between nodes in a network, for which the global minimum can be found efficiently. Our algorithm has a running time of O(N^3p^2 + N^2n) for a protein of length N. Adjusting the constraints on fragment length generates a set of optimized libraries with varying degrees of diversity. By comparing these optima for different sets of parents, we rapidly determine which parents yield the lowest energy libraries.", "date": "2004-07", "date_type": "published", "publication": "Protein Engineering, Design and Selection", "volume": "17", "number": "7", "publisher": "Oxford University Press", "pagerange": "589-594", "id_number": "CaltechAUTHORS:20111012-101511149", "issn": "1741-0126", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20111012-101511149", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NIH", "grant_number": "R01 GM068664-01" }, { "agency": "Army Research Office (ARO)", "grant_number": "DAAD19-03-D-0004" }, { "agency": "W. M. Keck Foundation" }, { "agency": "National Defense Science and Engineering Graduate (NDSEG) Fellowship" }, { "agency": "NIH Fellowship", "grant_number": "F32 GM64949-01" } ] }, "doi": "10.1093/protein/gzh067", "resource_type": "article", "pub_year": "2004", "author_list": "Endelman, Jeffrey B.; Silberg, Jonathan J.; et el." }, { "id": "https://authors.library.caltech.edu/records/mmpad-4bw69", "eprint_id": 4170, "eprint_status": "archive", "datestamp": "2023-08-22 01:16:36", "lastmod": "2023-10-16 17:38:47", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Spakowitz-A-J", "name": { "family": "Spakowitz", "given": "Andrew J." }, "orcid": "0000-0002-0585-1942" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Semiflexible polymer solutions. I. Phase behavior and single-chain statistics", "ispublished": "pub", "full_text_status": "public", "keywords": "polymer solutions; liquid crystal polymers; thermodynamic properties; SCF calculations; macromolecules; intramolecular mechanics; phase diagrams; fluctuations; liquid crystal phase transformations; eigenvalues and eigenfunctions", "note": "\u00a92003 American Institute of Physics. \n\nReceived 1 August 2003; accepted 30 September 2003. \n\nThis work was supported in part by the National Science Foundation (DMR-9970589).\n\nPublished - SPAjcp03.pdf
", "abstract": "We study the thermodynamics and single-chain statistics of wormlike polymer solutions with Maier\u2013Saupe-type interactions using self-consistent-field (SCF) theory. The SCF equations are derived using a systematic field-theoretical approach which yields the SCF equations as the lowest order approximation, but permits fluctuation corrections to be incorporated. We solve the SCF equations using the spheroidal functions, which provides a nonperturbative description of the thermodynamics and single-chain statistics in the nematic state for arbitrary degrees of nematic order. Several types of phase diagrams are predicted, with an emphasis on the limit of metastability (spinodal) associated with each phase. The shape and location of these spinodals suggest interesting scenarios for the phase transition kinetics. A large but finite persistence length is shown to significantly decrease the isotropic\u2013nematic transition temperature relative to that for rigid rods. In the nematic state, the mean-square end-to-end distance in the parallel and perpendicular directions are governed by two separate correlation lengths. An exact relationship between these correlation lengths and the eigenvalues of the spheroidal functions is provided, which reproduces the analytical expressions predicted from earlier studies in the limit of large nematic strength. The dominant contribution to the single-chain thermodynamics is shown to arise from small amplitude undulations in the directions perpendicular to the nematic direction; the presence of hairpins, though crucial for determining the dimensions of the polymer, has insignificant consequences on the single-chain thermodynamics.", "date": "2003-12-22", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "119", "number": "24", "publisher": "American Institute of Physics", "pagerange": "13113-13128", "id_number": "CaltechAUTHORS:SPAjcp03", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:SPAjcp03", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1063/1.1628669", "primary_object": { "basename": "SPAjcp03.pdf", "url": "https://authors.library.caltech.edu/records/mmpad-4bw69/files/SPAjcp03.pdf" }, "resource_type": "article", "pub_year": "2003", "author_list": "Spakowitz, Andrew J. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/c1qpp-qcp67", "eprint_id": 69715, "eprint_status": "archive", "datestamp": "2023-08-19 12:34:09", "lastmod": "2023-10-20 20:31:07", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bhattacharyya-S-M", "name": { "family": "Bhattacharyya", "given": "Sarika M." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Zewail-A-H", "name": { "family": "Zewail", "given": "Ahmed H." } } ] }, "title": "Dynamics of Water near a Protein Surface", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2003 American Chemical Society. \n\nReceived: July 31, 2003. Publication Date (Web): November 1, 2003. \n\nThis work was supported by the National Science Foundation. We thank Dr. Samir K. Pal for stimulating discussion and help. S.M.B. thanks Prof O. Bruno, Dr. A. Kamal, and A. Mukherjee for helpful discussions.", "abstract": "In this paper, we develop a model for the dynamics of water near a protein surface and compare with experimental results obtained with femtosecond resolution. The model consists of a layer of bound and free water molecules at the surface of the protein in dynamic equilibrium with each other, coupled to bulk water away from the protein surface. A previous model (Pal et al. J. Phys. Chem. B 2002, 106, 12376) considered the exchange in the layer without the coupling to the bulk. We find that water dynamics at the protein surface are described by two time scales, a fast, bulklike time scale, and a slower one more than 1 order of magnitude longer. The slow time scale, as in the previous model, is shown to be inversely proportional to the bound-to-free water conversion rate, k_2, but with a significant dependence on the free-to-bound conversion rate k_1, the diffusion of the free water molecules, and the thickness of the layer. This effect, identified as the feedback mechanism, is found to depend on the degree of orientation of the bound water molecules at the surface. The weight of the contribution of the slow component to the overall relaxation dynamics is shown to be inversely proportional to the slow decay time. For a heterogeneous surface with spatially varying k_2, the water dynamics in a probe region covering several sites is described by the cumulated effects from these water molecules, with the slow dynamics given by a sum of exponentials, with contributions inversely proportional to their respective decay times. To a very good degree, we find that this exponential behavior can be fitted to a single exponential; however, the apparent time scale does not represent that of any particular site. These conclusions are in good agreement with experimental results and provide important insight to the observed dynamical behavior.", "date": "2003-11-27", "date_type": "published", "publication": "Journal of Physical Chemistry B", "volume": "107", "number": "47", "publisher": "American Chemical Society", "pagerange": "13218-13228", "id_number": "CaltechAUTHORS:20160817-132622138", "issn": "1520-6106", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160817-132622138", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" } ] }, "doi": "10.1021/jp030943t", "resource_type": "article", "pub_year": "2003", "author_list": "Bhattacharyya, Sarika M.; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/a8t3r-bdj84", "eprint_id": 8781, "eprint_status": "archive", "datestamp": "2023-08-22 01:00:38", "lastmod": "2023-10-16 21:42:55", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Spakowitz-A-J", "name": { "family": "Spakowitz", "given": "Andrew J." }, "orcid": "0000-0002-0585-1942" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Semiflexible Polymer Confined to a Spherical Surface", "ispublished": "pub", "full_text_status": "public", "note": "\u00a92003 The American Physical Society. \n\nReceived 6 June 2003; published 16 October 2003. \n\nThis work was supported in part by the National Science Foundation (DMR-9970589).\n\nPublished - SPAprl03.pdf
", "abstract": "We develop a formalism for describing the kinematics of a wormlike chain confined to the surface of a sphere that simultaneously satisfies the spherical confinement and the inextensibility of the chain contour. We use this formalism to study the statistical behavior of the wormlike chain on a spherical surface. In particular, we provide an exact, closed-form expression for the mean square end-to-end distance that is valid for any value of chain length L, persistence length lp, and sphere radius R. We predict two qualitatively different behaviors for a long polymer depending on the ratio R/lp. For R/lp>4, the mean square end-to-end distance increases monotonically with the chain length, whereas for R/lp<4, a damped oscillatory behavior is predicted.", "date": "2003-10-17", "date_type": "published", "publication": "Physical Review Letters", "volume": "91", "number": "16", "publisher": "American Physical Society", "pagerange": "Art. No. 166102", "id_number": "CaltechAUTHORS:SPAprl03", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:SPAprl03", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1103/PhysRevLett.91.166102", "primary_object": { "basename": "SPAprl03.pdf", "url": "https://authors.library.caltech.edu/records/a8t3r-bdj84/files/SPAprl03.pdf" }, "resource_type": "article", "pub_year": "2003", "author_list": "Spakowitz, Andrew J. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/4t426-znj91", "eprint_id": 25334, "eprint_status": "archive", "datestamp": "2023-08-22 00:46:12", "lastmod": "2023-10-24 15:48:04", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Meyer-M-M", "name": { "family": "Meyer", "given": "Michelle M." } }, { "id": "Silberg-J-J", "name": { "family": "Silberg", "given": "Jonathan J." } }, { "id": "Voigt-C-A", "name": { "family": "Voigt", "given": "Christopher A." } }, { "id": "Endelman-J-B", "name": { "family": "Endelman", "given": "Jeffrey B." } }, { "id": "Mayo-S-L", "name": { "family": "Mayo", "given": "Stephen L." }, "orcid": "0000-0002-9785-5018" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Arnold-F-H", "name": { "family": "Arnold", "given": "Frances H." }, "orcid": "0000-0002-4027-364X" } ] }, "title": "Library analysis of SCHEMA-guided protein recombination", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Molecular Sequence Data; Recombination: Genetic; Models: Molecular; Protein Conformation; Algorithms; Recombinant Fusion Proteins; Amino Acid Sequence; beta-Lactamases; Protein Engineering; Peptide Library; DNA: Recombinant; Structure-Activity Relationship; chimera; lactamase; PSE-4; recombination; schema; TEM-1; directed evolution", "note": "\u00a9 2003 The Protein Society. Published by Cold Spring Harbor Laboratory Press. \n\nReceived February 17, 2003; Final revision May 1, 2003; Accepted May 1, 2003. \n\nThis work was supported by the Army Research Office, NIH Fellowship F32 GM64949-01 (J.J.S.), Howard Hughes Medical Institute graduate research fellowship (M.M.M.), National Defense\nScience and Engineering Fellowship (J.B.E.), National Science\nFoundation (C.A.V.), and Burroughs-Welcome Fund (C.A.V.).\nZ.G.W. acknowledges support by the W.M. Keck Foundation.\nS.L.M. is supported by the Howard Hughes Medical Institute, the\nRalph M. Parsons Foundation, and an IBM Shared University\nResearch Grant. \n\nThe publication costs of this article were defrayed in part by\npayment of page charges. This article must therefore be hereby\nmarked \"advertisement\" in accordance with 18 USC section 1734\nsolely to indicate this fact.", "abstract": "The computational algorithm SCHEMA was developed to estimate the disruption caused when amino acid residues that interact in the three-dimensional structure of a protein are inherited from different parents upon recombination. To evaluate how well SCHEMA predicts disruption, we have shuffled the distantly-related beta-lactamases PSE-4 and TEM-1 at 13 sites to create a library of 2^(14) (16,384) chimeras and examined which ones retain lactamase function. Sequencing the genes from ampicillin-selected clones revealed that the percentage of functional clones decreased exponentially with increasing calculated disruption (E = the number of residue-residue contacts that are broken upon recombination). We also found that chimeras with low E have a higher probability of maintaining lactamase function than chimeras with the same effective level of mutation but chosen at random from the library. Thus, the simple distance metric used by SCHEMA to identify interactions and compute E allows one to predict which chimera sequences are most likely to retain their function. This approach can be used to evaluate crossover sites for recombination and to create highly mosaic, folded chimeras.", "date": "2003-08", "date_type": "published", "publication": "Protein Science", "volume": "12", "number": "8", "publisher": "Wiley", "pagerange": "1686-1693", "id_number": "CaltechAUTHORS:20110913-173426256", "issn": "0961-8368", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110913-173426256", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Army Research Office (ARO)" }, { "agency": "NIH Postdoctoral Fellowship", "grant_number": "F32 GM64949-01" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "National Defense Science and Engineering Graduate (NDSEG) Fellowship" }, { "agency": "NSF" }, { "agency": "Burroughs-Welcome Fund" }, { "agency": "W. M. Keck Foundation" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "Ralph M. Parsons Foundation" }, { "agency": "IBM" } ] }, "doi": "10.1110/ps.0306603", "pmcid": "PMC2323955", "resource_type": "article", "pub_year": "2003", "author_list": "Meyer, Michelle M.; Silberg, Jonathan J.; et el." }, { "id": "https://authors.library.caltech.edu/records/8cz6q-40c04", "eprint_id": 8777, "eprint_status": "archive", "datestamp": "2023-08-22 00:36:26", "lastmod": "2023-10-16 21:42:46", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wickham-R-A", "name": { "family": "Wickham", "given": "Robert A." } }, { "id": "Shi-An-Chang", "name": { "family": "Shi", "given": "An-Chang" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nucleation of stable cylinders from a metastable lamellar phase in a diblock copolymer melt", "ispublished": "pub", "full_text_status": "public", "keywords": "nucleation; polymer blends; polymer melts; free energy", "note": "\u00a92003 American Institute of Physics. \n\n(Received 17 January 2003; accepted 13 March 2003) \n\nThe authors would like to thank Professor Martin Grant for helpful comments. This work was supported by the Natural Sciences and Engineering Research Council of Canada, the Research Corporation, and an Ontario Premier's Research Excellence Award. Z.G.W. acknowledges support by the U.S. National Science Foundation (Grant No. DMR-9970589).\n\nPublished - WICjcp03.pdf
", "abstract": "The nucleation of a droplet of stable cylinder phase from a metastable lamellar phase is examined within the single-mode approximation to the mean-field Landau\u2013Brazovskii model for diblock copolymer melts. By employing a variational ansatz for the droplet interfacial profile, an analytic expression for the interfacial free energy of an interface of arbitrary orientation between cylinders and lamellae is found. The interfacial free energy is anisotropic and is lower when the cylinder axis is perpendicular to the interface than when the cylinders lie along the interface. Consequently, the droplet shape computed via the Wulff construction is lens like, being flattened along the axis of the cylinders. The size of the critical droplet and the nucleation barrier are determined within classical nucleation theory. Near the lamellar\u2013cylinder phase boundary, where classical nucleation theory is applicable, critical droplets of size 30\u2013400 cylinders across with aspect ratios of 4\u201310 and nucleation barriers of (30\u201340)kBT are typically found. The general trend is to larger critical droplets, higher aspect ratios, and smaller nucleation barriers as the mean-field critical point is approached.", "date": "2003-06-08", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "118", "number": "22", "publisher": "American Institute of Physics", "pagerange": "10293-10305", "id_number": "CaltechAUTHORS:WICjcp03", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WICjcp03", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Natural Sciences and Engineering Research Council of Canada (NSERC)" }, { "agency": "Ontario Premier's Research Excellence Award" }, { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1063/1.1572461", "primary_object": { "basename": "WICjcp03.pdf", "url": "https://authors.library.caltech.edu/records/8cz6q-40c04/files/WICjcp03.pdf" }, "resource_type": "article", "pub_year": "2003", "author_list": "Wickham, Robert A.; Shi, An-Chang; et el." }, { "id": "https://authors.library.caltech.edu/records/wpb2k-tpf30", "eprint_id": 8768, "eprint_status": "archive", "datestamp": "2023-08-22 00:30:32", "lastmod": "2023-10-16 21:42:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Jianfang", "name": { "family": "Wang", "given": "Jianfang" } }, { "id": "Zhang-Hongdong", "name": { "family": "Zhang", "given": "Hongdong" } }, { "id": "Qiu-Feng", "name": { "family": "Qiu", "given": "Feng" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Yang-Yuliang", "name": { "family": "Yang", "given": "Yuliang" } } ] }, "title": "Nucleation in binary polymer blends: Effects of adding diblock copolymers", "ispublished": "pub", "full_text_status": "public", "keywords": "polymer blends; free energy; nucleation; phase separation; SCF calculations", "note": "\u00a92003 American Institute of Physics. \n\n(Received 24 January 2003; accepted 20 February 2003) \n\nFinancial support by the NSF of China and the Special Project for Fundamental Researches of the Ministry of Science and Technology is acknowledged. Z.G.W. acknowledges\nsupport by the US National Science Foundation (DMR-9970589).\n\nPublished - WANjcp03.pdf
", "abstract": "The effects of adding AB diblock copolymers to A/B binary blends on the structure and thermodynamics of critical nuclei are studied using the self-consistent field theory. At a fixed ratio of the amount of the two homopolymers, depending on the degree of polymerization and composition of the diblocks, their addition to the blends can either increase or decrease the nucleation free energy barrier relative to the pure A/B blends. The qualitative trend can be deduced from the shift in the coexistence boundary and the spinodal. The distribution of diblock copolymers in critical nuclei depends on the composition of the diblocks and the quench depth. Near the coexistence, symmetric diblocks exhibit surfactant behavior, being highly concentrated on the interface of the critical nuclei. Near the spinodal, they act more like co-solvent with a relatively uniform distribution.", "date": "2003-05-15", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "118", "number": "19", "publisher": "American Institute of Physics", "pagerange": "8997-9006", "id_number": "CaltechAUTHORS:WANjcp03", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WANjcp03", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "National Science Foundation of China" }, { "agency": "Special Project for Fundamental Researches, Ministry of Science and Technology" }, { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1063/1.1566941", "primary_object": { "basename": "WANjcp03.pdf", "url": "https://authors.library.caltech.edu/records/wpb2k-tpf30/files/WANjcp03.pdf" }, "resource_type": "article", "pub_year": "2003", "author_list": "Wang, Jianfang; Zhang, Hongdong; et el." }, { "id": "https://authors.library.caltech.edu/records/8pff7-mym59", "eprint_id": 3840, "eprint_status": "archive", "datestamp": "2023-08-21 23:30:44", "lastmod": "2023-10-16 16:11:11", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Concentration fluctuation in binary polymer blends: chi parameter, spinodal and Ginzburg criterion", "ispublished": "pub", "full_text_status": "public", "keywords": "polymer blends; polymer solutions; fluctuations; neutron diffraction", "note": "\u00a92002 American Institute of Physics. \n\n(Received 22 January 2002; accepted 5 April 2002) \n\nThis work is supported in part by the National Science Foundation (DMR-9970589) and by the China Natural Science Foundation. Helpful discussions with Nitash Balsara, Frank Bates, Karl Freed, Igal Szleifer, and Andrew Spakowitz are gratefully acknowledged.\n\nPublished - WANjcp02.pdf
", "abstract": "A theory for concentration fluctuations in binary polymer blends is developed using field-theoretic techniques. The theory provides a simple, unified framework for addressing a number of important issues. First, consideration of the fluctuation and correlation effects on different length scales leads to a clarification of three different chi parameters and their interrelationship. By incorporating interaction (modeled by the bare \u03c7b) and packing effects up to the polymer size, an effective chie emerges as the natural parameter for characterizing the molecular compatibility of the two polymer species. The measured quantity in small-angle neutron scattering (SANS) experiments is an apparent chia that includes long wavelength critical and spinodal fluctuations, and is related to \u03c7e through a self-consistent equation. \u03c7a exhibits the typical upward parabolic composition dependence observed in experiments and computer simulations. Second, a unified Ginzburg criterion involving both the composition and temperature (or temperaturelike variable) is derived that is applicable to both the critical and the off-critical spinodal regimes. The common characterization of the Ginzburg criterion in terms of a range of temperature (or temperaturelike variable) alone is generally inadequate. The molecular weight scaling proposed by de Gennes and Binder in the respective critical and off-critical spinodal regimes are recovered as special cases in the limit of large molecular weights. For typical molecular weights used in experiments the Ginzburg region is larger than commonly believed. Finally, the nature of the thermodynamic spinodal is examined. It is shown that a true off-critical thermodynamic spinodal does not exist in spatial dimensions less than 4. In its place, a pseudo-spinodal can be defined where the susceptibility reaches a finite maximum. The pseudo-spinodal precedes the mean-field spinodal but approaches the latter in the limit of infinite molecular weights. The pseudo-spinodal correlates strongly with the free energy barrier for nucleation becoming order kT. Thus it provides a kinetic limit for the physically accessible metastable state, beyond which phase separation may exhibit features characteristic of spinodal decomposition. The calculated location of the pseudo-spinodal for two samples used in a recent experiment of Balsara and co-workers agrees with the onset of spinodal-decomposition-like nucleation observed in the experiment.", "date": "2002-07-01", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "117", "number": "1", "publisher": "American Institute of Physics", "pagerange": "481-500", "id_number": "CaltechAUTHORS:WANjcp02", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WANjcp02", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9970589" }, { "agency": "National Natural Science Foundation of China" } ] }, "doi": "10.1063/1.1481761", "primary_object": { "basename": "WANjcp02.pdf", "url": "https://authors.library.caltech.edu/records/8pff7-mym59/files/WANjcp02.pdf" }, "resource_type": "article", "pub_year": "2002", "author_list": "Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/d72he-90a69", "eprint_id": 25453, "eprint_status": "archive", "datestamp": "2023-08-21 23:28:41", "lastmod": "2023-10-24 15:53:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Voigt-C-A", "name": { "family": "Voigt", "given": "Christopher A." } }, { "id": "Martinez-C", "name": { "family": "Martinez", "given": "Carlos" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Mayo-S-L", "name": { "family": "Mayo", "given": "Stephen L." }, "orcid": "0000-0002-9785-5018" }, { "id": "Arnold-F-H", "name": { "family": "Arnold", "given": "Frances H." }, "orcid": "0000-0002-4027-364X" } ] }, "title": "Protein building blocks preserved by recombination", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Beta-Lactamase; Globular-Proteins; Crystal-Structure; Evolution; Units; Resolution; Domains; Organization; Genes; Exons", "note": "\u00a9 2002 Nature Publishing Group. Published online: 3 June 2002; Corrected online: 10 June 2002. C.A.V. is supported by a National Science Foundation graduate research fellowship and the California Institute of Technology Initiative in Computational Molecular Biology, a Burroughs Wellcome funded program for science at the interface. Z.G.W. acknowledges the support by the W.M. Keck Foundation. S.L.M. is supported by the Howard Hughes Medical Institute, the Ralph M. Parsons Foundation and an IBM Shared University Research Grant. The PSE-4 gene and the PMON vector were provided by R.C. Levesque (Universit\u00e9 Laval, Qu\u00e9bec, Canada).", "abstract": "Borrowing concepts from the schema theory of genetic algorithms, we have developed a computational algorithm to identify the fragments of proteins, or schemas, that can be recombined without disturbing the integrity of the three-dimensional structure. When recombination leaves these schemas undisturbed, the hybrid proteins are more likely to be folded and functional. Crossovers found by screening libraries of several randomly shuffled proteins for functional hybrids strongly correlate with those predicted by this approach. Experimental results from the construction of hybrids of two beta-lactamases that share 40% amino acid identity demonstrate a threshold in the amount of schema disruption that the hybrid protein can tolerate. To the extent that introns function to promote recombination within proteins, natural selection would serve to bias their locations to schema boundaries.", "date": "2002-07", "date_type": "published", "publication": "Nature Structural Biology", "volume": "9", "number": "7", "publisher": "Nature Publishing Group", "pagerange": "553-558", "id_number": "CaltechAUTHORS:20110927-143229047", "issn": "1072-8368", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110927-143229047", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Caltech Initiative in Computational Molecular Biology" }, { "agency": "Burroughs Wellcome Fund" }, { "agency": "W. M. Keck Foundation" }, { "agency": "Howard Hughes Medical Institute (HHMI)" }, { "agency": "Ralph M. Parsons Foundation" }, { "agency": "IBM" } ] }, "doi": "10.1038/nsb805", "resource_type": "article", "pub_year": "2002", "author_list": "Voigt, Christopher A.; Martinez, Carlos; et el." }, { "id": "https://authors.library.caltech.edu/records/q52rm-wr972", "eprint_id": 8775, "eprint_status": "archive", "datestamp": "2023-08-21 23:01:49", "lastmod": "2023-10-16 21:42:41", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wood-S-M", "name": { "family": "Wood", "given": "Stephen M." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Nucleation in binary polymer blends: A self-consistent field study", "ispublished": "pub", "full_text_status": "public", "keywords": "polymer blends; free energy; SCF calculations; thermodynamic properties; metastable states; density functional theory; nucleation", "note": "\u00a92002 American Institute of Physics. \n\n(Received 30 July 2001; accepted 31 October 2001) \n\nThis work is supported in part by the National Science Foundation (DMR-9970589) and the Camille and Henry Dreyfus Foundation (TC-96-063). The authors thank Professor Nitash Balsara for sending us a preprint of their work Ref. 8 and for helpful discussions.\n\nPublished - WOOjcp02.pdf
", "abstract": "We study the structure and thermodynamics of the critical nuclei in metastable binary polymer blends using the self-consistent field method. At the mean-field level, our results are valid throughout the entire metastable region and provide a smooth crossover from the classical capillary-theory predictions near the coexistence curve to the density functional predictions of Cahn and Hilliard (properly transcribed into expressions involving the parameters of the binary polymer blends) near the spinodal. An estimate of the free energy barrier provides a quantitative criterion (the Ginzburg criterion) for the validity of the (mean-field) self-consistent approach. The region where mean-field theory is valid and where there can be a measurable nucleation rate is shown to be poorly described by the existing limiting theories; our predictions are therefore most relevant in this region. We discuss our results in connection with recent experimental observations by Balsara and co-workers.", "date": "2002-02-01", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "116", "number": "5", "publisher": "American Institute of Physics", "pagerange": "2289-2300", "id_number": "CaltechAUTHORS:WOOjcp02", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WOOjcp02", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9970589" }, { "agency": "Camille and Henry Dreyfus Foundation", "grant_number": "TC-96-063" } ] }, "doi": "10.1063/1.1429956", "primary_object": { "basename": "WOOjcp02.pdf", "url": "https://authors.library.caltech.edu/records/q52rm-wr972/files/WOOjcp02.pdf" }, "resource_type": "article", "pub_year": "2002", "author_list": "Wood, Stephen M. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/mb8tx-4tq27", "eprint_id": 79232, "eprint_status": "archive", "datestamp": "2023-08-19 08:58:44", "lastmod": "2023-10-26 14:43:23", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Lee-Hee-Hyun", "name": { "family": "Lee", "given": "Hee Hyun" } }, { "id": "Jeong-Woon-Yong", "name": { "family": "Jeong", "given": "Woon-Yong" } }, { "id": "Kim-Jin-Kon", "name": { "family": "Kim", "given": "Jin Kon" } }, { "id": "Ihn-Kyo-Jin", "name": { "family": "Ihn", "given": "Kyo Jin" } }, { "id": "Kornfield-J-A", "name": { "family": "Kornfield", "given": "Julia A." }, "orcid": "0000-0001-6746-8634" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Qi-Shuyan", "name": { "family": "Qi", "given": "Shuyan" } } ] }, "title": "Orientational Proliferation and Successive Twinning from Thermoreversible Hexagonal\u2212Body-Centered Cubic Transitions", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 2002 American Chemical Society. \n\nReceived 31 May 2001. Published online 3 January 2002. Published in print 1 January 2002 \n\nWe acknowledge helpful discussions with Professors T. Hashimoto, T. Lodge, S. Okamoto, C. Y. Ryu, S. Sakurai and A. C. Shi. This work was supported by KOSEF (97-05-02-03-01-3), by the Applied Rheology Center governed by KOSEF (2000 G0202), by TND projects supported by the Ministry of Science and Technology (MOST) and by NSF (CTS-9729443) and AFOSR (LC MURI). Synchrotron SAXS at the PLS (3C2 and 4C1 beam lines) was supported by MOST and Pohang Iron and Steel Co. (POSCO). Vector 4111 was kindly provided by Professor C. D. Han at the University of Akron.", "abstract": "The deterministic proliferation of the orientation of hexagonally packed cylinders (HEX) from the twinned body-centered cubic (BCC) phase is investigated by synchrotron small-angle X-ray scattering (SAXS) and rheo-optical methods for di- and triblock copolymers of styrene and isoprene (SI and SIS). Repeated heating and cooling cycles starting from an initially aligned HEX produce a proliferation of cylinder orientations from successively twinned BCC states. The evolution of the orientation distribution of HEX cylinders produces a decrease in the birefringence and increase in the modulus with each successive generation. The cylinder axes of the degenerate HEX states coincide with the \u3008111\u3009 directions of the twinned BCC due to the epitaxial growth of cylinders from the twinned BCC. The distribution of the cylinder axes of the degenerate HEX states among the \u3008111\u3009 directions of the twinned BCC is found to be affected by memory of the prior HEX state, which decays with annealing time in the BCC state.", "date": "2002-01-29", "date_type": "published", "publication": "Macromolecules", "volume": "35", "number": "3", "publisher": "American Chemical Society", "pagerange": "785-794", "id_number": "CaltechAUTHORS:20170720-075310985", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170720-075310985", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Korea Science and Engineering Foundation", "grant_number": "97-05-02-03-01-3" }, { "agency": "Korea Science and Engineering Foundation", "grant_number": "2000 G0202" }, { "agency": "NSF", "grant_number": "CTS-9729443" }, { "agency": "Air Force Office of Scientific Research (AFOSR)" }, { "agency": "Pohang Iron and Steel co." }, { "agency": "Ministry of Science and Technology (Korea)" } ] }, "doi": "10.1021/ma010951c", "resource_type": "article", "pub_year": "2002", "author_list": "Lee, Hee Hyun; Jeong, Woon-Yong; et el." }, { "id": "https://authors.library.caltech.edu/records/wwcjb-q9n50", "eprint_id": 8793, "eprint_status": "archive", "datestamp": "2023-08-21 22:44:54", "lastmod": "2023-10-16 21:43:23", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Spakowitz-A-J", "name": { "family": "Spakowitz", "given": "A. J." }, "orcid": "0000-0002-0585-1942" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Free expansion of elastic filaments", "ispublished": "pub", "full_text_status": "public", "note": "\u00a92001 The American Physical Society. \n\nReceived 16 May 2001; revised 13 July 2001; published 27 November 2001. \n\nThis work was supported in part by the National Science Foundation (DMR-9970589) and the Camille and Henry Dreyfus Foundation (TC-96-063).\n\nErratum: A. J. Spakowitz and Z.-G. Wang, Erratum: Free expansion of elastic filaments [Phys. Rev. E 64, 061802 (2001)], Phys. Rev. E 71, 059902 (2005).\n\nPublished - SPApre01.pdf
Erratum - SPApre01corr.pdf
", "abstract": "The dynamics of an elastic polymer filament undergoing contour length expansion is studied using computer simulation. The expansion occurs by development of transverse buckling waves that grow through a coarsening process. The growing buckles locally organize into a helical structure with a characteristic persistence length. The helical domain boundaries are eliminated from the relaxing structure by unwinding through the ends of the rod. The growth of the helical domains results in self-propulsive motion of the expanding rod, as one large helix spanning the entire chain relaxes during the late stages of the dynamics. Stability analyses and scaling arguments are provided to explain the simulation results.", "date": "2001-12", "date_type": "published", "publication": "Physical Review E", "volume": "64", "number": "6", "publisher": "American Physical Society", "pagerange": "Art. No. 061802", "id_number": "CaltechAUTHORS:SPApre01", "issn": "1063-651X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:SPApre01", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1103/PhysRevE.64.061802", "primary_object": { "basename": "SPApre01.pdf", "url": "https://authors.library.caltech.edu/records/wwcjb-q9n50/files/SPApre01.pdf" }, "related_objects": [ { "basename": "SPApre01corr.pdf", "url": "https://authors.library.caltech.edu/records/wwcjb-q9n50/files/SPApre01corr.pdf" } ], "resource_type": "article", "pub_year": "2001", "author_list": "Spakowitz, A. J. and Wang, Z.-G." }, { "id": "https://authors.library.caltech.edu/records/fqswt-pg086", "eprint_id": 2256, "eprint_status": "archive", "datestamp": "2023-08-21 22:40:13", "lastmod": "2023-10-13 23:17:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Dimitrakopoulos-P", "name": { "family": "Dimitrakopoulos", "given": "P." } }, { "id": "Brady-J-F", "name": { "family": "Brady", "given": "J. F." }, "orcid": "0000-0001-5817-9128" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Short- and intermediate-time behavior of the linear stress relaxation in semiflexible polymers", "ispublished": "pub", "full_text_status": "public", "keywords": "VISCOELASTICITY; MICRORHEOLOGY; FLUCTUATIONS", "note": "\u00a92001 The American Physical Society. \n\nReceived 19 April 2001; published 26 October 2001. \n\nThis work was supported by the Grant No. DMR-9970589 from the National Science Foundation. The computations were performed on multiprocessor computers provided by the National Center for Supercomputing Applications at Urbana, and the Center for Advanced Computing Research at Caltech. The authors wish to thank David Morse for providing access to his recent work [5] and for helpful discussions.\n\nPublished - DIMpre01.pdf
", "abstract": "The linear viscoelasticity of semiflexible polymers is studied through Brownian Dynamics simulations covering a broad range of chain stiffness and time scales. Our results agree with existing theoretical predictions in the flexible and stiff limits; however, we find that over a wide intermediate-time window spanning several decades, the stress relaxation is described by a single power law t^(-alpha), with the exponent alpha apparently varying continuously from 1/2 for flexible chains, to 5/4 for stiff ones. Our study identifies the limits of validity of the t^(-3/4) power law at short times predicted by recent theories. An additional regime is identified, the \"ultrastiff\" chains, where this behavior disappears. In the absence of Brownian motion, the purely mechanical stress relaxation produces a t^(-3/4) power law for both short and intermediate times.", "date": "2001-11", "date_type": "published", "publication": "Physical Review E", "volume": "64", "number": "5", "publisher": "American Physical Society", "pagerange": "Art. No. 050803", "id_number": "CaltechAUTHORS:DIMpre01", "issn": "1063-651X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:DIMpre01", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9970589" } ] }, "doi": "10.1103/PhysRevE.64.050803", "primary_object": { "basename": "DIMpre01.pdf", "url": "https://authors.library.caltech.edu/records/fqswt-pg086/files/DIMpre01.pdf" }, "resource_type": "article", "pub_year": "2001", "author_list": "Dimitrakopoulos, P.; Brady, J. F.; et el." }, { "id": "https://authors.library.caltech.edu/records/fsfp4-38b39", "eprint_id": 8769, "eprint_status": "archive", "datestamp": "2023-08-21 22:38:13", "lastmod": "2023-10-16 21:42:28", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kusaka-Isamu", "name": { "family": "Kusaka", "given": "Isamu" } }, { "id": "Oxtoby-D-W", "name": { "family": "Oxtoby", "given": "David W." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "On the direct evaluation of the equilibrium distribution of clusters by simulation. II", "ispublished": "pub", "full_text_status": "public", "keywords": "nucleation", "note": "\u00a92001 American Institute of Physics. \n\n(Received 1 May 2001; accepted 7 August 2001) \n\nThis work was supported by the National Science Foundation (Grant No. CHE-9800074). One of the authors (Z.-G.W.) acknowledges support from the Camille and Henry Dreyfus Foundation and a Grant by the Mobil Corporation.\n\nPublished - KUSjcp01.pdf
", "abstract": "We clarify some of the subtle issues surrounding the observational cluster method, a simulation technique for studying nucleation. The validity of the method is reaffirmed here. The condition of the compact cluster limit is quantified and its implications are elucidated in terms of the correct enumeration of configuration space.", "date": "2001-10-15", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "115", "number": "15", "publisher": "American Institute of Physics", "pagerange": "6998-7006", "id_number": "CaltechAUTHORS:KUSjcp01", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp01", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-9800074" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Mobil Oil Corporation" } ] }, "doi": "10.1063/1.1406977", "primary_object": { "basename": "KUSjcp01.pdf", "url": "https://authors.library.caltech.edu/records/fsfp4-38b39/files/KUSjcp01.pdf" }, "resource_type": "article", "pub_year": "2001", "author_list": "Kusaka, Isamu; Oxtoby, David W.; et el." }, { "id": "https://authors.library.caltech.edu/records/1jvdw-88d14", "eprint_id": 640, "eprint_status": "archive", "datestamp": "2023-08-21 22:06:23", "lastmod": "2023-10-13 21:54:36", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Voigt-C-A", "name": { "family": "Voigt", "given": "Christopher A." } }, { "id": "Mayo-S-L", "name": { "family": "Mayo", "given": "Stephen L." }, "orcid": "0000-0002-9785-5018" }, { "id": "Arnold-F-H", "name": { "family": "Arnold", "given": "Frances H." }, "orcid": "0000-0002-4027-364X" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Computational method to reduce the search space for directed protein evolution", "ispublished": "pub", "full_text_status": "public", "keywords": "in vitro directed evolution, computational protein design, combinatorial optimization, mean-field theory, protein tolerance", "note": "\u00a9 2001 by The National Academy of Sciences \n\nCommunicated by William A. Goddard III, California Institute of Technology, Pasadena, CA, December 22, 2000 (received for review May 26, 2000) \n\nC.A.V. is supported by a National Science Foundation graduate research fellowship and by a California Institute of Technology Initiative in Computational Molecular Biology, a Burroughs Wellcome-funded program for science at the interface. Financial support was provided by the Howard Hughes Medical Institute (S.L.M.). We thank Hue Sun Chan, Peter Kollman, Alan Fersht, John Yin, and Walter Fontana for advance readings of this manuscript and critical comments. \n\nThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked \"advertisement\" in accordance with 18 U.S.C. \u00a71734 solely to indicate this fact.\n\nPublished - VOIpnas01.pdf
", "abstract": "We introduce a computational method to optimize the in vitro evolution of proteins. Simulating evolution with a simple model that statistically describes the fitness landscape, we find that beneficial mutations tend to occur at amino acid positions that are tolerant to substitutions, in the limit of small libraries and low mutation rates. We transform this observation into a design strategy by applying mean-field theory to a structure-based computational model to calculate each residue's structural tolerance. Thermostabilizing and activity-increasing mutations accumulated during the experimental directed evolution of subtilisin E and T4 lysozyme are strongly directed to sites identified by using this computational approach. This method can be used to predict positions where mutations are likely to lead to improvement of specific protein properties.", "date": "2001-03-27", "date_type": "published", "publication": "Proceedings of the National Academy of Sciences of the United States of America", "volume": "98", "number": "7", "publisher": "National Academy of Sciences", "pagerange": "3778-3783", "id_number": "CaltechAUTHORS:VOIpnas01", "issn": "0027-8424", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:VOIpnas01", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF Graduate Research Fellowship" }, { "agency": "Caltech Initiative in Computational Molecular Biology" }, { "agency": "Burroughs Wellcome Fund" }, { "agency": "Howard Hughes Medical Institute (HHMI)" } ] }, "doi": "10.1073/pnas.051614498", "pmcid": "PMC31129", "primary_object": { "basename": "VOIpnas01.pdf", "url": "https://authors.library.caltech.edu/records/1jvdw-88d14/files/VOIpnas01.pdf" }, "resource_type": "article", "pub_year": "2001", "author_list": "Voigt, Christopher A.; Mayo, Stephen L.; et el." }, { "id": "https://authors.library.caltech.edu/records/nsd2w-cq956", "eprint_id": 25455, "eprint_status": "archive", "datestamp": "2023-08-21 21:48:27", "lastmod": "2023-10-24 15:53:09", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Voigt-C-A", "name": { "family": "Voigt", "given": "Christopher A." } }, { "id": "Mayo-S-L", "name": { "family": "Mayo", "given": "Stephen L." }, "orcid": "0000-0002-9785-5018" }, { "id": "Arnold-F-H", "name": { "family": "Arnold", "given": "Frances H." }, "orcid": "0000-0002-4027-364X" }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Computationally Focusing the Directed Evolution of Proteins", "ispublished": "pub", "full_text_status": "restricted", "keywords": "Mutagenesis; Directed Molecular Evolution; Proteins; Algorithms; Recombination: Genetic; DNA; Computational Biology; directed evolution; recombination; computational methods", "note": "\u00a9 2002 Wiley-Liss, Inc. Received 18 September 2001; Accepted 19 September 2001. Article first published online: 29 Jan 2002.", "abstract": "Directed evolution has proven to be a successful strategy for the modification of enzyme properties. To date, the preferred experimental procedure has been to apply mutations or crossovers randomly throughout the gene. With the emergence of powerful computational methods, it has become possible to develop focused combinatorial searches, guided by computer algorithms. Here, we describe several computational methods that have emerged to aid the optimization of mutant libraries, the targeting of specific residues for mutagenesis, and the design of recombination experiments.", "date": "2001", "date_type": "published", "publication": "Journal of Cellular Biochemistry", "volume": "84", "number": "S37", "publisher": "Wiley-Blackwell", "pagerange": "58-63", "id_number": "CaltechAUTHORS:20110927-154155139", "issn": "0730-2312", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110927-154155139", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1002/jcb.10066", "resource_type": "article", "pub_year": "2001", "author_list": "Voigt, Christopher A.; Mayo, Stephen L.; et el." }, { "id": "https://authors.library.caltech.edu/records/h4z97-qk353", "eprint_id": 8783, "eprint_status": "archive", "datestamp": "2023-08-21 21:36:50", "lastmod": "2023-10-16 21:43:00", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Bohbot-Raviv-Y", "name": { "family": "Bohbot-Raviv", "given": "Yardena" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Discovering New Ordered Phases of Block Copolymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a92000 The American Physical Society. \n\nReceived 30 March 2000. \n\nWe acknowledge financial support from the National Science Foundation, the Camille and Henry Dreyfus Foundation, and the Alfred P. Sloan Foundation.\n\nPublished - BOHprl00.pdf
", "abstract": "We propose a new and general method for discovering novel ordered phases of block copolymer melts. The method involves minimizing a free energy functional in an arbitrary unit cell with respect to the composition profile and the dimensions of the unit cell, without any prior assumption of the microphase symmetry. Varying the initial conditions allows to search for different stable and metastable structures. Application of this method to ABC star and linear triblock copolymers using an approximate free energy reveals new morphologies not yet observed in experiment.", "date": "2000-10", "date_type": "published", "publication": "Physical Review Letters", "volume": "85", "number": "16", "publisher": "American Physical Society", "pagerange": "3428-3431", "id_number": "CaltechAUTHORS:BOHprl00", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:BOHprl00", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Alfred P. Sloan Foundation" } ] }, "doi": "10.1103/PhysRevLett.85.3428", "primary_object": { "basename": "BOHprl00.pdf", "url": "https://authors.library.caltech.edu/records/h4z97-qk353/files/BOHprl00.pdf" }, "resource_type": "article", "pub_year": "2000", "author_list": "Bohbot-Raviv, Yardena and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/frdkt-y5904", "eprint_id": 8774, "eprint_status": "archive", "datestamp": "2023-08-22 14:14:19", "lastmod": "2023-10-16 21:42:39", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Qi-Shuyan", "name": { "family": "Qi", "given": "Shuyan" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Transient instability upon temperature quench in weakly ordered block copolymers", "ispublished": "pub", "full_text_status": "public", "keywords": "COPOLYMERS; QUENCH HARDENING; ORDER PARAMETERS; PHASE STABILITY; polymer blends; quenching (thermal)", "note": "\u00a91999 American Institute of Physics. \n\n(Received 22 July 1999; accepted 17 September 1999) \n\nWe thank Professors N.P. Balsara, M. Muthukumar, and M. Cross for helpful discussions. We particularly thank Professor N.P. Balsara for explaining his experimental findings in Ref. 34 to us which in large part provide the impetus for our work. Financial support from the National Science Foundation DMR-9531914), the Camille and Henry Dreyfus Foundation (TC-96-063), the Alfred P. Sloan Foundation (BR-3508), and the Department of Energy (BES, through Professor A. K. Chakraborty at UC Berkeley) is gratefully acknowledged.\n\nPublished - QISjcp99.pdf
", "abstract": "We report a novel transient instability upon temperature quench in weakly ordered block copolymer microphases possessing a soft direction or directions, such as the lamellar and hexagonal cylinder (HEX) phases. We show that reequilibration of the order parameter is accompanied by transient long wavelength undulation of the layers or cylinders\u2014with an initial wavelength that depends on the depth of the temperature quench\u2014that eventually disappears as the structure reaches its equilibrium at the new temperature. Such undulation leads to a transient transverse broadening of the scattering peaks near the Bragg positions. We argue that this instability might be responsible for the experimentally observed unusual ordering dynamics of the HEX phase of a diblock copolymer after quenching from the disordered state.", "date": "1999-12-15", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "111", "number": "23", "publisher": "American Institute of Physics", "pagerange": "10681-10688", "id_number": "CaltechAUTHORS:QISjcp99", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:QISjcp99", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9531914" }, { "agency": "Camille and Henry Dreyfus Foundation", "grant_number": "TC-96-063" }, { "agency": "Alfred P. Sloan Foundation", "grant_number": "BR-3508" }, { "agency": "Department of Energy (DOE)" } ] }, "doi": "10.1063/1.480422", "primary_object": { "basename": "QISjcp99.pdf", "url": "https://authors.library.caltech.edu/records/frdkt-y5904/files/QISjcp99.pdf" }, "resource_type": "article", "pub_year": "1999", "author_list": "Qi, Shuyan and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/8bq96-cn948", "eprint_id": 8772, "eprint_status": "archive", "datestamp": "2023-08-22 14:13:27", "lastmod": "2023-10-16 21:42:35", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kusaka-Isamu", "name": { "family": "Kusaka", "given": "Isamu" } }, { "id": "Oxtoby-D-W", "name": { "family": "Oxtoby", "given": "David W." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "On the direct evaluation of the equilibrium distribution of clusters by simulation", "ispublished": "pub", "full_text_status": "public", "keywords": "probability; free energy; nucleation", "note": "Copyright \u00a9 1999 American Institute of Physics. \n\n(Received 22 April 1999; accepted 31 August 1999) \n\nThis work was supported by the National Science Foundation (Grant No. CHE-9800074). Z.-G.W. acknowledges support from the Camille and Henry Dreyfus Foundation, the Alfred P. Sloan Foundation, the National Science Foundation and a Grant by the Mobil Corporation.\n\nPublished - KUSjcp99.pdf
", "abstract": "An expression is derived that relates the average population of a particular type of cluster in a metastable vapor phase of volume Vtot to the probability, estimated by simulation, of finding this cluster in a system of volume V taken inside Vtot, where V<", "date": "1999-12-08", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "111", "number": "22", "publisher": "American Institute of Physics", "pagerange": "9958-9964", "id_number": "CaltechAUTHORS:KUSjcp99", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp99", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE-9800074" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Mobil Oil Corporation" } ] }, "doi": "10.1063/1.480349", "primary_object": { "basename": "KUSjcp99.pdf", "url": "https://authors.library.caltech.edu/records/8bq96-cn948/files/KUSjcp99.pdf" }, "resource_type": "article", "pub_year": "1999", "author_list": "Kusaka, Isamu; Oxtoby, David W.; et el." }, { "id": "https://authors.library.caltech.edu/records/gcxm5-c2s27", "eprint_id": 2976, "eprint_status": "archive", "datestamp": "2023-08-22 12:46:46", "lastmod": "2023-10-13 23:50:33", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kusaka-Isamu", "name": { "family": "Kusaka", "given": "I." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" }, { "id": "Seinfeld-J-H", "name": { "family": "Seinfeld", "given": "J. H." }, "orcid": "0000-0003-1344-4068" } ] }, "title": "Binary nucleation of sulfuric acid-water: Monte Carlo simulation", "ispublished": "pub", "full_text_status": "public", "keywords": "hydrogen compounds; water; nucleation; Monte Carlo methods; free energy; dissociation; ab initio calculations", "note": "\u00a9 1998 American Institute of Physics. \n\nReceived 11 November 1997; accepted 22 January 1998. \n\nThe authors wish to express gratitude to Dr. Tsan H. Lay for helpful discussions regarding the free energy of the reaction Eq. (9) and performing ab initio calculation for us and to Dr. Markku Kulmala for providing them with the program to perform a calculation using the classical theory. This work was supported by National Science Foundation Grant No. ATM-9614105. Simulation is performed in large part using the parallel computer system operated by Caltech Center for Advanced Computing Research (CACR). Z.-G.W. acknowledges support from the Camille and Henry Dreyfus Foundation, the Alfred P. Sloan Foundation, and the National Science Foundation. We also acknowledge support by a grant from the Mobil Corporation.\n\nPublished - KUSjcp98b.pdf
", "abstract": "We have developed a classical mechanical model for the H2SO4/H2O binary system. Monte Carlo simulation was performed in a mixed ensemble, in which the number of sulfuric acid molecules is fixed while that of water molecules is allowed to fluctuate. Simulation in this ensemble is computationally efficient compared to conventional canonical simulation, both in sampling very different configurations of clusters relevant in nucleation and in evaluating the free energy of cluster formation. The simulation yields molecular level information, such as the shape of the clusters and the dissociation behavior of the acid molecule in the cluster. Our results indicate that the clusters are highly nonspherical as a result of the anisotropic intermolecular interactions and that a cluster with a given number of acid molecules has several very different conformations, which are close in free energy and hence equally relevant in nucleation. The dissociation behavior of H2SO4 in a cluster differs markedly from that in bulk solution and depends sensitively on the assumed value of the free energy f(hb) of the dissociation reaction H2SO4+H2O-HSO4-. H3O+. In a small cluster, no dissociation is observed. As the cluster size becomes larger, the probability of having an HSO4-. H3O+ ion pair increases. However, in clusters relevant in nucleation, the resulting ion pairs remain in contact; about 240 water molecules are required to observe behavior that resembles that in bulk solution. If a larger value of f(hb) is assumed to reflect its uncertainty, the probability of dissociation becomes negligible. A reversible work surface obtained for a condition typical of vapor to liquid nucleation suggests that the rate-limiting step of new particle formation is a binary collision of two hydrated sulfuric acid molecules. The ion pairs formed by dissociation play a key role in stabilizing the resulting cluster. The reversible work surface is sensitive to the assumed value of f(hb), thus pointing to the need for an accurate estimate of the quantity either by ab initio calculations or experiments.", "date": "1998-04-22", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "108", "number": "16", "publisher": "American Institute of Physics", "pagerange": "6829-6848", "id_number": "CaltechAUTHORS:KUSjcp98b", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp98b", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "ATM-9614105" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Mobil Oil Corporation" } ] }, "doi": "10.1063/1.476097", "primary_object": { "basename": "KUSjcp98b.pdf", "url": "https://authors.library.caltech.edu/records/gcxm5-c2s27/files/KUSjcp98b.pdf" }, "resource_type": "article", "pub_year": "1998", "author_list": "Kusaka, I.; Wang, Z.-G.; et el." }, { "id": "https://authors.library.caltech.edu/records/yw0xe-1t936", "eprint_id": 8773, "eprint_status": "archive", "datestamp": "2023-08-22 12:41:07", "lastmod": "2023-10-16 21:42:37", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kusaka-Isamu", "name": { "family": "Kusaka", "given": "I." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" }, { "id": "Seinfeld-J-H", "name": { "family": "Seinfeld", "given": "J. H." }, "orcid": "0000-0003-1344-4068" } ] }, "title": "Direct evaluation of the equilibrium distribution of physical clusters by a grand canonical Monte Carlo simulation", "ispublished": "pub", "full_text_status": "public", "keywords": "molecular clusters; digital simulation; fluctuations; Monte Carlo methods", "note": "\u00a9 1998 American Institute of Physics. \n\n(Received 29 September 1997; accepted 25 November 1997) \n\nThe authors wish to express gratitude to Professor Howard Reiss and his co-workers for the series of insightful papers (Refs. 1\u20136) and fruitful discussions, which led them to appreciate the importance of the physical clusters in the context of nucleation theory. This work was supported by National Science Foundation Grant No. ATM-9614105. Z.-G.W. acknowledges support from the Camille and Henry Dreyfus Foundation, the Alfred P. Sloan Foundation, and the National Science Foundation. We also acknowledge support by a grant from the Mobil Corporation.\n\nPublished - KUSjcp98a.pdf
", "abstract": "A new approach to cluster simulation is developed in the context of nucleation theory. This approach is free of any arbitrariness involved in the definition of a cluster. Instead, it preferentially and automatically generates the physical clusters, defined as the density fluctuations that lead to nucleation, and determines their equilibrium distribution in a single simulation, thereby completely bypassing the computationally expensive free energy evaluation that is necessary in a conventional approach. The validity of the method is demonstrated for a single component system using a model potential for water under several values of supersaturation.", "date": "1998-03-01", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "108", "number": "9", "publisher": "American Institute of Physics", "pagerange": "3416-3423", "id_number": "CaltechAUTHORS:KUSjcp98a", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp98a", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "ATM-9614105" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Alfred P. Sloan Foundation" }, { "agency": "Mobil Oil Corporation" } ] }, "doi": "10.1063/1.475741", "primary_object": { "basename": "KUSjcp98a.pdf", "url": "https://authors.library.caltech.edu/records/yw0xe-1t936/files/KUSjcp98a.pdf" }, "resource_type": "article", "pub_year": "1998", "author_list": "Kusaka, I.; Wang, Z.-G.; et el." }, { "id": "https://authors.library.caltech.edu/records/9b8zt-b6w86", "eprint_id": 85283, "eprint_status": "archive", "datestamp": "2023-08-19 02:01:27", "lastmod": "2023-10-18 18:03:26", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Gido-S-P", "name": { "family": "Gido", "given": "Samuel P." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Interfacial Curvature in Graft and Diblock Copolymers and Implications for Long-Range Order in Cylindrical Morphologies", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1997 American Chemical Society. \n\nReceived March 14, 1997; Revised Manuscript Received September 2, 1997. Publication Date (Web): November 3, 1997. \n\nWe wish to acknowledge Darrin J. Pochan for providing TEM and SAXS data for this paper and Chin Lee for useful discussions. S.P.G. acknowledges funding from the Army Research Office in the form of an Army Young Investigator Award DAAH04-95-I-0305. Use of TEM instrumentation in the W. M. Keck Electron Microscopy Laboratory at the University of Massachusetts-Amherst is acknowledged, as is the use of central facilities of the Materials Research Science and Engineering Center (MRSEC) at the University of Massachusetts. Z.-G.W acknowledges support from the National Science Foundation (Grant Nos. ASC-9217368 and DMR-9531914), the Camille and Henry Dreyfus Foundation (Award No. TC-96-063) and the Alfred P. Sloan Foundation (Award No. BR-3508).", "abstract": "Microstructures of block copolymers in the strong segregation limit are characterized by well-defined interfaces separating the different block materials into domains on a nanometer scale. In this paper, we address the effects of architectural and conformational asymmetry of the blocks on the interfacial curvature characteristics and on the degree of long-range order in the cylindrical morphologies. Experimental (TEM and SAXS) curvature data from polyisoprene\u2212polystyrene (I2S) simple graft block copolymers and from polyisoprene\u2212poly(tert-butyl methacrylate) (PtBMA) linear, conformationally asymmetric diblock copolymers are presented and compared to data from polyisoprene\u2212polystyrene linear diblock copolymers. The experimental data are elucidated by a simple curvature free energy model which accounts for core-space-filling without explicitly specifying the shape of the microdomain. This model allows the prediction of preferred interfacial curvature characteristics as a function of molecular architecture. Good agreement is obtained between the theoretically calculated mean and Gaussian curvatures and the experimentally measured values. A key finding is that the degree of frustration, as measured by the difference between the free energy of the preferred curvature of a given block copolymer and that of the nearest accessible space-filling structure (such as the cylindrical structure), is correlated with the degree of long-range order.", "date": "1997-11-03", "date_type": "published", "publication": "Macromolecules", "volume": "30", "number": "22", "publisher": "American Chemical Society", "pagerange": "6771-6782", "id_number": "CaltechAUTHORS:20180313-141816020", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180313-141816020", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Army Research Office (ARO)", "grant_number": "DAAH04-95-I-0305" }, { "agency": "NSF", "grant_number": "ASC-9217368" }, { "agency": "NSF", "grant_number": "DMR-9531914" }, { "agency": "Camille and Henry Dreyfus Foundation", "grant_number": "TC-96-063" }, { "agency": "Alfred P. Sloan Foundation", "grant_number": "BR-3508" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/ma9703564", "resource_type": "article", "pub_year": "1997", "author_list": "Gido, Samuel P. and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/gmnhk-2s648", "eprint_id": 102032, "eprint_status": "archive", "datestamp": "2023-08-19 01:41:22", "lastmod": "2023-10-19 23:45:50", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Martin-J-I", "name": { "family": "Martin", "given": "J. I." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" }, { "id": "Zuckerman-D", "name": { "family": "Zuckerman", "given": "D." } }, { "id": "Bruinsma-R", "name": { "family": "Bruinsma", "given": "R." } }, { "id": "Pincus-P", "name": { "family": "Pincus", "given": "P." } } ] }, "title": "Forces between Surfaces with Weakly End-Adsorbed Polymers", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 1997 Les Editions de Physique. \n\nReceived 9 October 1996, revised 10 April 1997, accepted 22 April 1997.", "abstract": "We study the interaction forces between two plates in a semi-dilute solution of polymers each having one weakly adsorbing end-group. We show that this system exhibits both repulsive and attractive interactions of comparable magnitude and well-separated length scales: when the plate separation is within a range of order the end-to-end distance of the end-adsorbed polymer, repulsion arises with a magnitude of \u03f5 \u03a6/Na\u00b3 where \u03f5 is the end-adsorption energy, N is the degree of polymerization, a is the Kuhn length and \u03a6 the volume fraction of the polymer. This repulsion is due to desorption of the end-adsorbed chains. At plate separations of order the correlation length of the solution, a depletion attraction sets in with a magnitude that scales with the bulk osmotic pressure.", "date": "1997-08", "date_type": "published", "publication": "Journal de Physique II", "volume": "7", "number": "8", "publisher": "EDP Sciences", "pagerange": "1111-1121", "id_number": "CaltechAUTHORS:20200320-144002936", "issn": "1155-4312", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200320-144002936", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "collection": "CaltechAUTHORS", "doi": "10.1051/jp2:1997175", "resource_type": "article", "pub_year": "1997", "author_list": "Martin, J. I.; Wang, Z.-G.; et el." }, { "id": "https://authors.library.caltech.edu/records/45tw9-67g24", "eprint_id": 88029, "eprint_status": "archive", "datestamp": "2023-08-19 01:37:31", "lastmod": "2023-10-18 21:38:01", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Qi-Shuyan", "name": { "family": "Qi", "given": "Shuyan" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "On the Nature of the Perforated Layer Phase in Undiluted Diblock Copolymers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1997 American Chemical Society. \n\nReceived February 13, 1997; Revised Manuscript Received May 1, 1997. \n\nWe thank F. S. Bates, D. A. Hajduk, and E. L. Thomas for helpful discussions. This research is supported in part by the National Science Foundation (Grant Nos. ASC-9217368 and DMR-9531914), the Camille and Henry Dreyfus Foundation (Award No. TC-96-063), and the Alfred P. Sloan Foundation (Award No. BR-3508).", "abstract": "The nature, stability, and mechanism of formation of the block copolymer perforated lamellar structure are elucidated. This structure is shown to develop from the anisotropic fluctuations of the lamellar phase when it reaches its spinodal. It is proposed that there can be two different perforated lamellar structures, one based on a hexagonal close packed (hcp) lattice and one based on a body-centered cubic (bcc) lattice, with nearly degenerate free energy. In the framework of a Leibler-type free energy functional, it is shown that the perforated lamellar structure is only pseudostable (corresponding to a saddle point in the free energy surface) in the weak-segregation limit but can become metastable in the intermediate-segregation regime. Calculation of the fluctuation spectrum of metastable perforated lamellar structures enables us to explain in a simple and consistent manner several puzzling structural data from small-angle neutron scattering studies.", "date": "1997-07-28", "date_type": "published", "publication": "Macromolecules", "volume": "30", "number": "15", "publisher": "American Chemical Society", "pagerange": "4491-4497", "id_number": "CaltechAUTHORS:20180719-153004411", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180719-153004411", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "ASC-9217368" }, { "agency": "NSF", "grant_number": "DMR-9531914" }, { "agency": "Camille and Henry Dreyfus Foundation", "grant_number": "TC-96-063" }, { "agency": "Alfred P. Sloan Foundation", "grant_number": "BR-3508" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/ma970206t", "resource_type": "article", "pub_year": "1997", "author_list": "Qi, Shuyan and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/14d66-hpm50", "eprint_id": 8795, "eprint_status": "archive", "datestamp": "2023-08-22 11:32:48", "lastmod": "2023-10-16 21:43:27", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Qi-Shuyan", "name": { "family": "Qi", "given": "Shuyan" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Kinetics of phase transitions in weakly segregated block copolymers: Pseudostable and transient states", "ispublished": "pub", "full_text_status": "public", "note": "\u00a91997 The American Physical Society. \n\n(Received 2 August 1996) \n\nThis research is supported in part by the National Science Foundation (Grant Nos. ASC-9217368 and DMR-9531914) and the Camille and Henry Dreyfus Foundation (Award No. TC-96-063).\n\nPublished - QISpre97.pdf
", "abstract": "We study the kinetics of order-disorder and order-order transitions in weakly segregated diblock copolymers using a time-dependent Ginzburg-Landau (TDGL) approach. In particular, we investigate the microstructural change as well as the order-parameter evolution after a sudden temperature jump from one phase to another. Direct numerical simulation of the TDGL equations shows that depending on the extent of the temperature jump, these transitions often occur in several stages and can involve nontrivial intermediate states. For example, we find that transition from the lamellar phase to the hexagonal cylinder phase goes through a perforated lamellar state within a certain temperature range. The numerical results are elucidated by a multimode analysis under the single-wave-number approximation. The analysis reveals that the geometric characteristics of the free energy surface, particularly saddle points and ridgelike features, are responsible for the nontrivial intermediate states on the kinetic pathways. On the basis of this analysis, a generalized kinetic ``phase diagram'' is constructed, which is able to account for all the different scenarios observed in the numerical simulation. Our results are discussed in connection with available experimental observations. In particular, we suggest the possibility that the perforated-modulated lamellar structures obtained by Bates and co-workers [I. W. Hamley, K. A. Koppi, J. H. Rosedale, F. S. Bates, K. Almdal, and K. Mortensen, Macromolecules 26, 5959 (1993); S. F\u00f6rster, A. K. Khandpur, J. Zhao, F. S. Bates, I. W. Hamley, A. J. Ryan, and W. Bras, Macromolecules 27, 6922 (1994)] may be kinetic, intermediate states rather than new equilibrium phases.", "date": "1997-02", "date_type": "published", "publication": "Physical Review E", "volume": "55", "number": "2", "publisher": "American Physical Society", "pagerange": "1682-1697", "id_number": "CaltechAUTHORS:QUIpre97", "issn": "1063-651X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:QUIpre97", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "ASC-9217368" }, { "agency": "NSF", "grant_number": "DMR-9531914" }, { "agency": "Camille and Henry Dreyfus Foundation", "grant_number": "TC-96-063" } ] }, "doi": "10.1103/PhysRevE.55.1682", "primary_object": { "basename": "QISpre97.pdf", "url": "https://authors.library.caltech.edu/records/14d66-hpm50/files/QISpre97.pdf" }, "resource_type": "article", "pub_year": "1997", "author_list": "Qi, Shuyan and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/g8r7x-3y962", "eprint_id": 88041, "eprint_status": "archive", "datestamp": "2023-08-19 00:24:54", "lastmod": "2023-10-18 21:39:08", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Martin-J-I", "name": { "family": "Martin", "given": "J. I." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" }, { "id": "Schick-M", "name": { "family": "Schick", "given": "M." } } ] }, "title": "Effects of Polymer Brush Self-Assembly on Spreading and Thin Film Stability", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1996 American Chemical Society. \n\nReceived April 1, 1996. In Final Form: June 20, 1996. \n\nWe thank Jacob Klein and Nily Dan for stimulating discussion. We thank especially Jacob Klein for bringing our attention to refs 2 and 3, which initiated this study. Financial support from the National Science Foundation under Grants DMR9220733 and ASC9217368 and the Camille and Henry Dreyfus Foundation is gratefully acknowledged.", "abstract": "This paper discusses the modification of several spreading properties of a liquid on a solid surface by the addition of end-adsorbing polymers. End-adsorption of the polymers at the liquid\u2212solid interface decreases the interfacial free energy. If this decrease is sufficient to overcome the negative spreading power of an otherwise nonspreading liquid, the liquid will spread on the surface. Using a self-consistent field method, we construct a phase diagram for spreading of a liquid drop of fixed volume as a function of the concentration of end-adsorbing polymers and the energy of end-adsorption to the surface. The equilibrium thickness of a spread film is also calculated and is shown to be closely related to the thickness of a self-assembled polymer brush in an unbounded fluid but relatively insensitive to the bare spreading power of the liquid or the Hamaker constant, which determine the equilibrium thickness of a film of a simple liquid. When a solid surface of a given area is covered by a film thicker than the predicted equilibrium thickness of a spread film, an instability due to the depletion attraction causes the excess liquid to form drops on top of the spread film of the equilibrium thickness.", "date": "1996-10-02", "date_type": "published", "publication": "Langmuir", "volume": "12", "number": "20", "publisher": "American Chemical Society", "pagerange": "4950-4959", "id_number": "CaltechAUTHORS:20180719-162404743", "issn": "0743-7463", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180719-162404743", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "DMR-9220733" }, { "agency": "NSF", "grant_number": "ASC-9217368" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "collection": "CaltechAUTHORS", "doi": "10.1021/la960305k", "resource_type": "article", "pub_year": "1996", "author_list": "Martin, J. I.; Wang, Z.-G.; et el." }, { "id": "https://authors.library.caltech.edu/records/09ymf-g9g19", "eprint_id": 88080, "eprint_status": "archive", "datestamp": "2023-08-20 07:23:54", "lastmod": "2023-10-18 21:43:58", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Johnson-R-D", "name": { "family": "Johnson", "given": "R. D." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" }, { "id": "Arnold-F-H", "name": { "family": "Arnold", "given": "F. H." }, "orcid": "0000-0002-4027-364X" } ] }, "title": "Surface Site Heterogeneity and Lateral Interactions in Multipoint Protein Adsorption", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1996 American Chemical Society. \n\nReceived: August 15, 1995; In Final Form: NoVember 1, 1995. \n\nThis research is supported by the National Science Foundation. F.H.A. acknowledges an NSF PYI award and a fellowship from the David and Lucile Packard Foundation. R.D.J. acknowledges a predoctoral training fellowship from the U. S. National Institute of General Medical Sciences, Pharmacology Sciences Program.", "abstract": "Studies carried out using engineered proteins have demonstrated that protein adsorption to functional surfaces involves multiple interactions between specific groups on the protein and complementary binding sites distributed on the surface. A consequence of multipoint interactions is that protein binding affinity should depend strongly on the distribution of surface binding sites. In this investigation we present a thermodynamic framework for multipoint protein binding to a random arrangement of surface binding sites that also includes lateral interactions among adsorbed protein molecules. This framework results in reversible adsorption behavior analogous to that predicted by the Temkin model and chromatographic behavior analogous to that predicted by the \"stoichiometric displacement\" model (SDM). Using this framework we can now interpret the semiempirical parameters obtained using these models for protein binding in chromatographic systems in terms of thermodynamic parameters for protein\u2212surface interactions. We show a correlation between Temkin model parameters for a series of cytochrome c variants in immobilized metal affinity chromatography (IMAC) that is consistent with protein adsorption to a nonuniform arrangement of surface binding sites. Lateral interactions among adsorbed protein molecules are shown to be insignificant for this system.", "date": "1996-03-21", "date_type": "published", "publication": "Journal of Physical Chemistry", "volume": "100", "number": "12", "publisher": "American Chemical Society", "pagerange": "5134-5139", "id_number": "CaltechAUTHORS:20180720-141711681", "issn": "0022-3654", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180720-141711681", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF" }, { "agency": "David and Lucile Packard Foundation" }, { "agency": "NIH Predoctoral Fellowship" } ] }, "doi": "10.1021/jp9523682", "resource_type": "article", "pub_year": "1996", "author_list": "Johnson, R. D.; Wang, Z.-G.; et el." }, { "id": "https://authors.library.caltech.edu/records/39gww-2pq39", "eprint_id": 4256, "eprint_status": "archive", "datestamp": "2023-08-22 10:55:11", "lastmod": "2023-10-16 17:40:42", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Qi-Shuyan", "name": { "family": "Qi", "given": "Shuyan" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Kinetic Pathways of Order-Disorder and Order-Order Transitions in Weakly Segregated Microstructured Systems", "ispublished": "pub", "full_text_status": "public", "note": "\u00a91996 The American Physical Society \n\nReceived 17 July 1995 \n\nWe thank S. T. Milner, G. H. Fredrickson, and P.-G. de Gennes for helpful discussions. This research is supported in part by donors of the Petroleum Research Fund, administered by the American Chemical Society, and by the National Science Foundation (Grant No. ASC-9217368).\n\nPublished - QISprl96.pdf
", "abstract": "The kinetics of hexagonal to disordered and hexagonal to body-centered-cubic phase transitions in weakly segregated, microstructured systems (e.g., diblock copolymers) is studied using a time-dependent Ginzburg-Landau (TDGL) approach. Both computer simulation of the TDGL equation and analysis of a simplified two-mode model reveal nontrivial pathways during the transition.", "date": "1996-03-04", "date_type": "published", "publication": "Physical Review Letters", "volume": "76", "number": "10", "publisher": "American Physical Society", "pagerange": "1679-1682", "id_number": "CaltechAUTHORS:QISprl96", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:QISprl96", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "American Chemical Society Petroleum Research Fund" }, { "agency": "NSF", "grant_number": "ASC-9217368" } ] }, "doi": "10.1103/PhysRevLett.76.1679", "primary_object": { "basename": "QISprl96.pdf", "url": "https://authors.library.caltech.edu/records/39gww-2pq39/files/QISprl96.pdf" }, "resource_type": "article", "pub_year": "1996", "author_list": "Qi, Shuyan and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/2hn96-37618", "eprint_id": 2063, "eprint_status": "archive", "datestamp": "2023-09-13 16:43:31", "lastmod": "2023-10-23 20:36:56", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kusaka-Isamu", "name": { "family": "Kusaka", "given": "I." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" }, { "id": "Seinfeld-J-H", "name": { "family": "Seinfeld", "given": "J. H." }, "orcid": "0000-0003-1344-4068" } ] }, "title": "Ion-induced nucleation. II. Polarizable multipolar molecules", "ispublished": "pub", "full_text_status": "public", "keywords": "DENSITY FUNCTIONAL METHOD; FREE ENERGY; INTERACTIONS; INTERIONIC POTENTIALS; INTERMOLECULAR FORCES; MOLECULAR IONS; NUCLEATION; STATISTICAL MECHANICS; SUPERSATURATION; VAPOR CONDENSATION", "note": "\u00a9 1995 American Institute of Physics. \n\nReceived 11 July 1995; accepted 18 August 1995. \n\nThis work is supported by National Science Foundation Grant No. ATM-9307603. Part I of this work is Kusaka et al. [J. Chem. Phys. 102, 913 (1995)]. [Ref. 15]\n\nPublished - KUSjcp95b.pdf
", "abstract": "Density functional theory is applied to ion-induced nucleation of polarizable multipolar molecules. The asymmetric nature of the ion-molecule interaction is shown to cause the sign preference in ion-induced nucleation. When the ion-molecule interaction is weak, the observed sign preference is consistent with that of the bare ion-molecule interaction potential and decreases with increasing supersaturation. However, as the ion-molecule interaction becomes stronger, the sign preference in the reversible work exhibits some nontrivial behavior. For molecular parameters applicable for CS2 and CH4, the predicted values of the reversible work of nucleation depend on the sign of the ion charge, yielding a difference in the nucleation rate by factors of 10 to 10^(2) and 10 to 10^(5), respectively.", "date": "1995-11-22", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "103", "number": "20", "publisher": "American Institute of Physics", "pagerange": "8993-9009", "id_number": "CaltechAUTHORS:KUSjcp95b", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp95b", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "ATM-9307603" } ] }, "doi": "10.1063/1.470089", "primary_object": { "basename": "KUSjcp95b.pdf", "url": "https://authors.library.caltech.edu/records/2hn96-37618/files/KUSjcp95b.pdf" }, "resource_type": "article", "pub_year": "1995", "author_list": "Kusaka, I.; Wang, Z.-G.; et el." }, { "id": "https://authors.library.caltech.edu/records/mzeck-m0h45", "eprint_id": 86633, "eprint_status": "archive", "datestamp": "2023-08-20 05:35:55", "lastmod": "2023-10-18 19:48:40", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Martin-J-I", "name": { "family": "Martin", "given": "J. I." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Polymer Brushes: Scaling, Compression Forces, Interbrush Penetration, and Solvent Size Effects", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1995 American Chemical Society. \n\nReceived: August 9, 1994; In Final Form: November 8, 1994. \n\nThis paper is dedicated to Professor Stuart A. Rice, with great respect and deep appreciation. \n\nThis research is supported in part by the Petroleum Research Fund, administered by The American Chemical Society.", "abstract": "This work discusses the results of a self-consistent-field calculation of conformational and thermodynamic properties of polymers end-grafted to a surface in athermal solvents. Three primary issues are addressed. First, we address the question raised recently by Carignano and Szleifer as to whether the second virial treatment of previous numerical and analytical self-consistent-field theories provides an adequate description of polymer brushes. We show that, for grafted chains that are sufficiently long, there exists a broad range of grafting densities where the lateral pressure and the brush thickness both scale as predicted by the second virial treatment. For shorter chains (of 100 monomers or less), no distinct scaling regime is observed. A related effect due to finite chain lengths is the interpenetration of brushes upon compression and its importance to compression forces. We find that, even for quite large chains (of up to 1000 monomers), there is significant interbrush penetration at high compression. However, the force profiles are relatively insensitive to penetration at such high compressions. Instead, finite chain lengths affect the interaction forces most prominently at the onset of the interactions. Next, we address the crossover from wet brushes to dry brushes as the molecular weight of the solvent increases. This crossover is driven purely by entropic effects and is interpreted on the basis of the conformation of the polymeric solvent molecules in the vicinity of the brush. It is found that the state of the brush is determined by two crossover scaling variables, the ratio of the degree of polymerization of the free and grafted chains, N_f/N_g and N_f\u03c3^2, where \u03c3 is the grafting density. Finally, we investigate brush configurations and interactions in mixed solvents. It is observed that, for polymer brushes in a solution of mixed free polymers and monomers, there are three distinct regimes in the interactions between two brushes. Upon the onset of the interaction, the brushes attract one another as the solvent is transferred from an unfavorable proximity to the brush to the infinite reservoir. Then, there is a very rapidly increasing repulsive force as the brushes begin to overlap and the remainder of the free polymer is removed from the system. Once all of the polymeric component has been squeezed out of the brushes, the compression becomes indistinguishable from the compression of brushes in a monomeric solvent.", "date": "1995-03-02", "date_type": "published", "publication": "Journal of Physical Chemistry", "volume": "99", "number": "9", "publisher": "American Chemical Society", "pagerange": "2833-2844", "id_number": "CaltechAUTHORS:20180525-133235076", "issn": "0022-3654", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180525-133235076", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1021/j100009a045", "resource_type": "article", "pub_year": "1995", "author_list": "Martin, J. I. and Wang, Z.-G." }, { "id": "https://authors.library.caltech.edu/records/9sv90-ejf87", "eprint_id": 8770, "eprint_status": "archive", "datestamp": "2023-08-22 10:17:12", "lastmod": "2023-10-16 21:42:30", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Kusaka-Isamu", "name": { "family": "Kusaka", "given": "I." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Z.-G." }, "orcid": "0000-0002-3361-6114" }, { "id": "Seinfeld-J-H", "name": { "family": "Seinfeld", "given": "J. H." }, "orcid": "0000-0003-1344-4068" } ] }, "title": "Ion-induced nucleation: A density functional approach", "ispublished": "pub", "full_text_status": "public", "keywords": "NUCLEATION; DENSITY FUNCTIONAL METHOD; DIPOLES; MOLECULES; REVERSIBLE PROCESSES; IONS; SUPERSATURATION; ASYMMETRY; ENHANCEMENT; VAPORS; DROPLETS", "note": "\u00a9 1995 American Institute of Physics. \n\n(Received 4 August 1994; accepted 4 October 1994) \n\nThis work was supported by National Science Foundation Grant No. ATM-9307603.\n\nPublished - KUSjcp95a.pdf
", "abstract": "Density functional theory is applied to ion-induced nucleation of dipolar molecules. The predicted reversible work shows a sign preference, resulting in a difference in the nucleation rate by a factor of 10\u201310^2, for realistic values of model parameters. The sign effect is found to decrease systematically as the supersaturation is increased. The asymmetry of a molecule is shown to be directly responsible for the sign preference in ion-induced nucleation.", "date": "1995-01-08", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "102", "number": "2", "publisher": "American Institute of Physics", "pagerange": "913-924", "id_number": "CaltechAUTHORS:KUSjcp95a", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:KUSjcp95a", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "ATM-9307603" } ] }, "doi": "10.1063/1.469158", "primary_object": { "basename": "KUSjcp95a.pdf", "url": "https://authors.library.caltech.edu/records/9sv90-ejf87/files/KUSjcp95a.pdf" }, "resource_type": "article", "pub_year": "1995", "author_list": "Kusaka, I.; Wang, Z.-G.; et el." }, { "id": "https://authors.library.caltech.edu/records/nhbjj-yxy42", "eprint_id": 8792, "eprint_status": "archive", "datestamp": "2023-08-22 09:50:56", "lastmod": "2023-10-16 21:43:20", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Golubovi\u0107-L", "name": { "family": "Golubovi\u0107", "given": "Leonardo" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Kardar-Parisi-Zhang model and anomalous elasticity of two- and three-dimensional smectic-A liquid crystals", "ispublished": "pub", "full_text_status": "public", "note": "\u00a91994 The American Physical Society. \n\nReceived 4 October 1993. \n\nWe are grateful to Tom Lubensky and Robijn Bruinsma for discussions. Z.G.W. acknowledges support of the Camille and Henry Dreyfus Foundation. [L.G. acknowledges suuport of the National Science Foundation -- West Virginia Experimental Program to Stimulate Competitive Research.]\n\nErratum: Kardar-Parisi-Zhang model and anomalous elasticity of two- and three-dimensional smectic-A liquid crystals [Phys. Rev. E 49, 2567 (1994)]. Phys. Rev. E 50, 4265 (1994).\n\nPublished - GOLpre94.pdf
Erratum - GOLpre94corr.pdf
", "abstract": "We reveal a deep theoretical relationship between equilibrium statistical physics of smectic-A liquid crystals and nonequilibrium statistical physics of the Kardar-Parisi-Zhang dynamical model [M. Kardar, G. Parisi, and Y.-C. Zhang, Phys. Rev. Lett. 56, 889 (1986)] for interfaces growing in the presence of a flux of incoming particles. This relationship provides an exact approach to study Landau-Peierls phenomena and anomalous elasticity of two-dimensional smectic-A liquid crystals. Also, it yields prediction of an unusual elastic critical point in three-dimensional smectic-A liquid crystals with broken inversion symmetry (head-to-tail packing of layers). We discuss the elasticity and fluctuations of these unusual smectic-A phases.", "date": "1994-04", "date_type": "published", "publication": "Physical Review E", "volume": "49", "number": "4", "publisher": "American Physical Society", "pagerange": "2567-2578", "id_number": "CaltechAUTHORS:GOLpre94", "issn": "1063-651X", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:GOLpre94", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "NSF" } ] }, "doi": "10.1103/PhysRevE.49.2567", "primary_object": { "basename": "GOLpre94corr.pdf", "url": "https://authors.library.caltech.edu/records/nhbjj-yxy42/files/GOLpre94corr.pdf" }, "related_objects": [ { "basename": "GOLpre94.pdf", "url": "https://authors.library.caltech.edu/records/nhbjj-yxy42/files/GOLpre94.pdf" } ], "resource_type": "article", "pub_year": "1994", "author_list": "Golubovi\u0107, Leonardo and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/3atng-z7q03", "eprint_id": 8771, "eprint_status": "archive", "datestamp": "2023-08-22 09:46:57", "lastmod": "2023-10-16 21:42:32", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Response and instabilities of the lamellar phase of diblock copolymers under uniaxial stress", "ispublished": "pub", "full_text_status": "public", "keywords": "COPOLYMERS; LAMELLAE; PHASE STUDIES; COMPRESSION; TENSION; LAYERS; SEGREGATION; NONLINEAR PROBLEMS; FREE ENERGY; MECHANICAL PROPERTIES; STRAINS; SQUARE LATTICES; ORDER\u2212DISORDER TRANSFORMATIONS; ISOTROPY; MELTING; INSTABILITY; THERMODYNAMICS; SPINODAL DECOMPOSITION; EQUILIBRIUM", "note": "Copyright \u00a9 1994 American Institute of Physics. \n\n(Received 16 August 1993; accepted 12 October 1993) \n\nThe author. wishes to thank J.A. Kornfield for a critical reading of the manuscript and helpful comments. This research was supported in part by a Fellowship from The Institute for Advanced Studies, The Hebrew University of Jerusalem, where the work began. Acknowledgment is also made to the Donors of The Petroleum Research Fund, administered by the American Chemical Society, for additional support.\n\nPublished - WANjcp94.pdf
", "abstract": "We study the quasistatic behavior of the lamellar phase of diblock copolymers under uniaxial compression and tension along the normal direction of the layers, in both the weak segregation limit (WSL) and the strong segregation limit (SSL). In the SSL, we derive a (nonlinear) continuum free energy description of the system in terms of local displacement of the lamellar layers, and use this free energy to study the mechanical behaviors. While compression induces the usual Hookian elastic response (for strains or stresses that are not too large), tension leads to square-lattice wave undulations in the transverse directions when the strain exceeds a critical value. In the WSL close to the order\u2013disorder transition temperature, compression can ``melt'' the lamellar phase to the isotropic phase; such a melting can take the form of three types of instabilities, a quasithermodynamic instability, a spinodal at controlled strain, and a mechanical instability at controlled stress. It is shown that the third instability always precedes the second one under controlled-stress conditions. For a weakly first-order transition, the quasithermodynamic instability precedes the mechanical instability; but for a (hypothetical) second-order transition, the mechanical instability appears first as the stress is increased. In the case of tension, a transverse square-lattice wave deformation again develops at a critical strain. This deformation can be followed by a subsequent melting of types similar to the compressional case, upon further increase of the stress or strain. In both the SSL and WSL, the modulus undergoes an abrupt decrease when layer undulation develops, to a value 7/15 of that before the onset of undulation. Because the critical strain for the onset of undulation is usually very small, the modulus for tension will appear different from the modulus for compression, the former being 7/15 of the latter. As a result of this decrease in the modulus, melting of the lamellar phase in the WSL will occur at larger strains under tension than under compression.", "date": "1994-02-01", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "100", "number": "3", "publisher": "American Institute of Physics", "pagerange": "2298-2309", "id_number": "CaltechAUTHORS:WANjcp94", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WANjcp94", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Institute for Advanced Study, Hebrew University of Jerusalem" }, { "agency": "American Chemical Society Petroleum Research Fund" } ] }, "doi": "10.1063/1.466528", "primary_object": { "basename": "WANjcp94.pdf", "url": "https://authors.library.caltech.edu/records/3atng-z7q03/files/WANjcp94.pdf" }, "resource_type": "article", "pub_year": "1994", "author_list": "Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/c4s8y-3a278", "eprint_id": 8776, "eprint_status": "archive", "datestamp": "2023-08-22 09:32:44", "lastmod": "2023-10-16 21:42:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Spatially modulated phases in monolayers of mixed surfactants", "ispublished": "pub", "full_text_status": "public", "keywords": "SURFACTANTS; MONOLAYERS; COMMENSURATE PHASES; FLUID\u2212FLUID INTERFACES; MATHEMATICAL MODELS; ASYMMETRY; SOLID\u2212FLUID INTERFACES; SUBSTRATES; PHASE STUDIES; FRUSTRATION; ORDER\u2212DISORDER TRANSFORMATIONS; FLUCTUATIONS", "note": "\u00a91993 American Institute of Physics. \n\n(Received 7 April 1993; accepted 25 May 1993) \n\nThis paper is dedicated, with great respect and deep appreciation, to Professor Stuart A. Rice in honor of his 60th birthday. This work has been supported in part by the Camille and Henry Dreyfus New Faculty Award Program and by the Caltech Consortium for Chemistry and Chemical Engineering; founding members E. I. Du Pont de Menours and Company, Inc., Eastman Kodak Company, and Minnesota Mining and Manufacturing Company.\n\nPublished - WANjcp93.pdf
", "abstract": "We present a theoretical study of spatially modulated phases in self-assembled monolayers of mixed surfactants. We propose two models which are appropriate, respectively, for monolayers at a fluid\u2013fluid interface and monolayers on a solid substrate. We show that in both cases, the molecular shape asymmetry, coupled with the local composition variation, can lead to spontaneous formation of periodic structures. In the case of liquid-supported monolayers, the molecular shape asymmetry is manifested as a spontaneous curvature of each component of the film, which induces periodic variations both in the composition of the amphiphiles and in the height profile of the interface (ripples). In the case of solid-supported monolayers, the shape asymmetry is reflected in the spontaneous splay of the orientation of the amphiphiles, and the spatial modulation involves the composition as well as the orientation of the amphiphilic molecules. We analyze these models in some detail near the critical region, where we highlight the roles played by various length scales in determining the critical wavelength. We show that gravity has some very subtle and nontrivial effects for a liquid-supported, tension-free monolayer. We also present some preliminary results for the low temperature cases.", "date": "1993-09-01", "date_type": "published", "publication": "Journal of Chemical Physics", "volume": "99", "number": "5", "publisher": "American Institute of Physics", "pagerange": "4191-4200", "id_number": "CaltechAUTHORS:WANjcp93", "issn": "0021-9606", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:WANjcp93", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Caltech Consortium in Chemistry and Chemical Engineering" }, { "agency": "E. I. DuPont de Nemours and Company, Inc." }, { "agency": "Eastman Kodak Company" }, { "agency": "Minnesota Mining and Manufacturing Company" } ] }, "doi": "10.1063/1.1481761", "primary_object": { "basename": "WANjcp93.pdf", "url": "https://authors.library.caltech.edu/records/c4s8y-3a278/files/WANjcp93.pdf" }, "resource_type": "article", "pub_year": "1993", "author_list": "Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/tbedz-8ka84", "eprint_id": 8782, "eprint_status": "archive", "datestamp": "2023-08-22 09:15:33", "lastmod": "2023-10-16 21:42:58", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Selinger-J-V", "name": { "family": "Selinger", "given": "Jonathan V." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Bruinsma-R-F", "name": { "family": "Bruinsma", "given": "Robijn F." } }, { "id": "Knobler-C-M", "name": { "family": "Knobler", "given": "Charles M." } } ] }, "title": "Chiral symmetry breaking in Langmuir monolayers and smectic films", "ispublished": "pub", "full_text_status": "public", "note": "\u00a91993 The American Physical Society. \n\nReceived 24 November 1992. \n\nWe thank J. Maclennan, D.R. Nelson, J.M. Schnur, and M. Seul for many helpful discussions. This research was supported by the Donors of The Petrolum Research Fund, administered by the American Chemical Society, and by the Caltech Consortium in Chemistry and Chemical Engineering (founding members: E.I. Du Pont de Nemours and Company, Inc., Eastman Kodak Company, and Minnesota Mining and Manufacturing Company).\n\nPublished - SELprl93.pdf
", "abstract": "Langmuir monolayers and freely suspended smectic films can exhibit a spontaneous breaking of chiral symmetry. The order parameter that characterizes this symmetry breaking is coupled to variations in the direction of molecular tilt. As a result, chiral symmetry breaking leads to the spontaneous formation of complex equilibrium patterns with either 1D or 2D modifications in the direction of molecular tilt. A Landau theory for this pattern formation gives a general phase diagram, which includes a uniform nonchiral phase, a striped pattern, a square lattice, and a uniform chiral phase.", "date": "1993-02-22", "date_type": "published", "publication": "Physical Review Letters", "volume": "70", "number": "8", "publisher": "American Physical Society", "pagerange": "1139-1142", "id_number": "CaltechAUTHORS:SELprl93", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:SELprl93", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "American Chemical Society Petroleum Research Fund" }, { "agency": "Caltech Consortium in Chemistry and Chemical Engineering" }, { "agency": "E. I. DuPont de Nemours and Company, Inc." }, { "agency": "Eastman Kodak Company" }, { "agency": "Minnesota Mining and Manufacturing Company" } ] }, "doi": "10.1103/PhysRevLett.70.1139", "primary_object": { "basename": "SELprl93.pdf", "url": "https://authors.library.caltech.edu/records/tbedz-8ka84/files/SELprl93.pdf" }, "resource_type": "article", "pub_year": "1993", "author_list": "Selinger, Jonathan V.; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/kf8qx-ndb25", "eprint_id": 85277, "eprint_status": "archive", "datestamp": "2023-08-20 02:22:56", "lastmod": "2023-10-18 18:02:51", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Costas-M-E", "name": { "family": "Costas", "given": "Maria Eugenia" } }, { "id": "Gelbart-W-M", "name": { "family": "Gelbart", "given": "William M." } } ] }, "title": "Flexible micelles and the n \u2192 0 vector spin model", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1993 American Chemical Society. \n\nReceived: July 17, 1992; In Final Form: October 28, 1992. \n\nIt is a pleasure to thank Dr. Jaime Ruiz-Garcia and Profs. Avi Ben-Shaul and Bob Scott for several helpful discussions. This work was partially supported by the U.S. National Science Foundation (Grant CHE92-01166 to W.M.G.) and the Camille and Henry Dreyfus New Faculty Award Program (Z.-G.W.). M.E.C. is grateful for a postdoctoral fellowship from the Universidad Nacional Autonoma de Mexico, which helped support her work at UCLA.", "abstract": "We show how the n \u2192 0 vector spin model is especially naturally suited for treating the solution properties of\nflexible, cylindrical micelles. In particular, an isomorphism is established between coupling constants in the\nspin Hamiltonian and surfactant energies in the micellar situation. The appropriately generalized n \u2192 0 vector\nspin model is then solved in mean field approximation and shown to describe the phenomenon of mi cellar growth\nat low concentrations and crossover through the semidilute regime. Osmotic pressure and average aggregation\nnumber are calculated as a function of concentration, and our basic approach is compared and contrasted with\nthose for \"ordinary\" and \"living\" polymer solutions.", "date": "1993-02-11", "date_type": "published", "publication": "Journal of Physical Chemistry", "volume": "97", "number": "6", "publisher": "American Chemical Society", "pagerange": "1237-1242", "id_number": "CaltechAUTHORS:20180313-105825017", "issn": "0022-3654", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180313-105825017", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE 92-01166" }, { "agency": "Camille and Henry Dreyfus Foundation" }, { "agency": "Universidad Nacional Aut\u00f3noma de M\u00e9xico (UNAM)" } ] }, "doi": "10.1021/j100108a021", "resource_type": "article", "pub_year": "1993", "author_list": "Wang, Zhen-Gang; Costas, Maria Eugenia; et el." }, { "id": "https://authors.library.caltech.edu/records/weccx-z5e73", "eprint_id": 102026, "eprint_status": "archive", "datestamp": "2023-08-20 01:52:42", "lastmod": "2023-10-19 23:45:25", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Turner-D-C", "name": { "family": "Turner", "given": "David C." } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" }, { "id": "Gruner-S-M", "name": { "family": "Gruner", "given": "Sol M." } }, { "id": "Mannock-D-A", "name": { "family": "Mannock", "given": "David A." } }, { "id": "McElhaney-R-N", "name": { "family": "McElhaney", "given": "Ronald N." } } ] }, "title": "Structural study of the inverted cubic phases of di-dodecyl alkyl-\u03b2-D-glucopyranosyl-rac-glycerol", "ispublished": "pub", "full_text_status": "public", "note": "\u00a9 1992 Les Editions de Physique. \n\nReceived 3 June 1992, accepted in final form 2 July 1992.", "abstract": "We present a quantitative study of the bicontinuous cubic phases in the didodecyl alkyl-\u03b2-D-glucopyranosyl-rac-glycerol (rac-di-12:0 \u03b2-GlcDAG) lipid-water system. A temperature-composition phase diagram determined using X-ray diffraction shows Ia3d and Pn3/Pn3m cubic phase regions in addition to inverted hexagonal (H^(II)) and several lamellar phase regions. The diffraction data was used to determine the lattice repeat vector, d, and, using suitable models, the lipid monolayer thickness, d_L, for all temperatures and compositions in the diagram. The models chosen for the cubic phases were based on lipid bilayers straddling infinitely periodic minimal surfaces (IPMS) as described previously in the literature [1]. Using the structural data derived from the phase diagram, the lyotropic phase transition between the two cubics was modeled by a simple curvature free energy theory. A new result of this theory was an estimate for the Gaussian curvature bending modulus of the lipid monolayer. The model was found to quantitatively describe the phase transition, particularly for phase behavior at low hydration. Our model suggests some universal features should be present in any system that shows non-lamellar phases and we discuss those features with respect to the phase diagrams available in the literature.", "date": "1992-11", "date_type": "published", "publication": "Journal de Physique II", "volume": "2", "number": "11", "publisher": "EDP Sciences", "pagerange": "2039-2063", "id_number": "CaltechAUTHORS:20200320-123553945", "issn": "1155-4312", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200320-123553945", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "doi": "10.1051/jp2:1992250", "resource_type": "article", "pub_year": "1992", "author_list": "Turner, David C.; Wang, Zhen-Gang; et el." }, { "id": "https://authors.library.caltech.edu/records/kj1qz-p4h90", "eprint_id": 8784, "eprint_status": "archive", "datestamp": "2023-08-22 09:03:11", "lastmod": "2023-10-16 21:43:02", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Golubovi\u0107-L", "name": { "family": "Golubovi\u0107", "given": "Leonardo" } }, { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Anharmonic elasticity of smectics A and the Kardar-Parisi-Zhang model", "ispublished": "pub", "full_text_status": "public", "note": "\u00a91992 The American Physical Society. \n\nReceived 7 August 1992. \n\nWe thank Tom Lubensky and Robijn Bruinsma for useful discussions. This work was supported in part by the Camille and Henry Dreyfus Foundation. \n\nNote added. -- After this work was done, a related work, Ref. [21], was brought to our attention.\n\nPublished - GOLprl92.pdf
", "abstract": "We relate anharmonic equilibrium thermal fluctuations of smectics A to fluctuations of the Kardar-Parisi-Zhang (KPZ) dynamical model for a growing interface. The KPZ model in 1+1 dimensions is one to one related to a 2D smectic elastic model whose scaling behavior is then obtained exactly. The KPZ model in 2+1 dimensions maps into an elastic critical point of 3D smectics A with broken inversion symmetry (head-to-tail packing of layers). We discuss the elasticity and fluctuations of these novel smectic-A phases.", "date": "1992-10-26", "date_type": "published", "publication": "Physical Review Letters", "volume": "69", "number": "17", "publisher": "American Physical Society", "pagerange": "2535-2538", "id_number": "CaltechAUTHORS:GOLprl92", "issn": "0031-9007", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:GOLprl92", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1103/PhysRevLett.69.2535", "primary_object": { "basename": "GOLprl92.pdf", "url": "https://authors.library.caltech.edu/records/kj1qz-p4h90/files/GOLprl92.pdf" }, "resource_type": "article", "pub_year": "1992", "author_list": "Golubovi\u0107, Leonardo and Wang, Zhen-Gang" }, { "id": "https://authors.library.caltech.edu/records/rtad1-vwq86", "eprint_id": 85287, "eprint_status": "archive", "datestamp": "2023-08-20 01:32:47", "lastmod": "2023-10-18 18:03:44", "type": "article", "metadata_visibility": "show", "creators": { "items": [ { "id": "Wang-Zhen-Gang", "name": { "family": "Wang", "given": "Zhen-Gang" }, "orcid": "0000-0002-3361-6114" } ] }, "title": "Curvature instability of diblock copolymer bilayers", "ispublished": "pub", "full_text_status": "restricted", "note": "\u00a9 1992 American Chemical Society. \n\nReceived November 14, 1991; Revised Manuscript Received April 6, 1992. \n\nI thank S. A. Safran for helpful discussions and a critical reading of the manuscript. Financial support from the National Science Foundation (Grant CHE88-16059) through Professor W. M. Gelbart at the University of California, Los Angeles, CA, where part of this work was conducted, and from The Camille and Henry Dreyfus New Faculty Awards Program is gratefully acknowledged.", "abstract": "The curvature expansion of the free energy for diblock copolymers aggregated into bilayers\nis studied for strongly incompatible diblocks. It is shown that sufficient asymmetry in the di block composition\nleads to an instability of the flat bilayer with respect to spherical or saddle-splay deformations: when the\nbilayer consists of two (diblock copolymer) monolayers each having a strong tendency to curve convexly\ntoward the solvent, i.e., when the outer block is much larger than the inner block, spherical vesicles become\nfavored by the curvature elastic free energy over flat bilayers. In the opposite case, saddle-splay deformations\nare favored.", "date": "1992-07-06", "date_type": "published", "publication": "Macromolecules", "volume": "25", "number": "14", "publisher": "American Chemical Society", "pagerange": "3702-3705", "id_number": "CaltechAUTHORS:20180313-152006067", "issn": "0024-9297", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180313-152006067", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "CHE88-16059" }, { "agency": "Camille and Henry Dreyfus Foundation" } ] }, "doi": "10.1021/ma00040a015", "resource_type": "article", "pub_year": "1992", "author_list": "Wang, Zhen-Gang" } ]